diff --git a/IOT_API/Controllers/Asset/EquipmentController.cs b/IOT_API/Controllers/Asset/EquipmentController.cs
index fbdd3f0..5447a45 100644
--- a/IOT_API/Controllers/Asset/EquipmentController.cs
+++ b/IOT_API/Controllers/Asset/EquipmentController.cs
@@ -1,9 +1,12 @@
 using Microsoft.AspNetCore.Mvc;
 using Model;
+using Model.Dto.Asset;
 using Model.Entity.Asset;
+using Model.Mapper;
 using Service.Interface;
 using SqlSugar;
 using System.Collections.Generic;
+using System.IO;
 using System.Threading.Tasks;
 
 namespace IOT_API.Controllers.Asset
@@ -11,16 +14,21 @@ namespace IOT_API.Controllers.Asset
     /// <summary>
     /// 资产管理 - 设备台账控制器
     /// </summary>
-    [Route("api/Equipment")]  //资产管理模块下的设备管理接口
     [ApiController]
-    [Route("api/asset/equipment")]
+    [Route("api/asset/equipment")] //资产管理模块下的设备管理接口
     public class EquipmentController : ControllerBase
     {
         private readonly IEquipmentService _equipmentService;
+        private readonly IEquipmentAttachmentService _attachmentService;
+        private readonly IWebHostEnvironment _webHostEnvironment;
 
-        public EquipmentController(IEquipmentService equipmentService)
+        public EquipmentController(IEquipmentService equipmentService,
+            IEquipmentAttachmentService attachmentService,
+            IWebHostEnvironment webHostEnvironment)
         {
             _equipmentService = equipmentService;
+            _attachmentService = attachmentService;
+            _webHostEnvironment = webHostEnvironment;
         }
 
         /// <summary>
@@ -32,22 +40,27 @@ namespace IOT_API.Controllers.Asset
         /// <param name="categoryId">设备分类Id（0表示不过滤）</param>
         /// <param name="status">设备状态（不传表示不过滤）</param>
         [HttpGet("list")]
-        public async Task<Result<List<EquipmentEntity>>> GetList(int pageIndex = 1, int pageSize = 10,
+        public async Task<Result<List<EquipmentDto>>> GetList(int pageIndex = 1, int pageSize = 10,
             string? keyword = null, long categoryId = 0, EquipmentStatusEnum? status = null)
         {
             RefAsync<int> total = 0;
             var result = await _equipmentService.GetPagedAsync(pageIndex, pageSize, total, keyword, categoryId, status);
             Response.Headers["X-Total-Count"] = total.Value.ToString();
-            return result;
+            return result.IsSuccess
+                ? Result<List<EquipmentDto>>.Success(result.Data.ToDtoList())
+                : Result<List<EquipmentDto>>.Error(result.Msg);
         }
 
         /// <summary>
         /// 查询全部设备（不分页，供下拉选择等场景使用）
         /// </summary>
         [HttpGet("all")]
-        public async Task<Result<List<EquipmentEntity>>> GetAll()
+        public async Task<Result<List<EquipmentDto>>> GetAll()
         {
-            return await _equipmentService.GetAllAsync();
+            var result = await _equipmentService.GetAllAsync();
+            return result.IsSuccess
+                ? Result<List<EquipmentDto>>.Success(result.Data.ToDtoList())
+                : Result<List<EquipmentDto>>.Error(result.Msg);
         }
 
         /// <summary>
@@ -55,29 +68,33 @@ namespace IOT_API.Controllers.Asset
         /// </summary>
         /// <param name="id">设备主键 Id</param>
         [HttpGet("{id}")]
-        public async Task<Result<EquipmentEntity>> GetById(long id)
+        public async Task<Result<EquipmentDto>> GetById(long id)
         {
-            return await _equipmentService.GetByIdAsync(id);
+            var res = await _equipmentService.GetByIdAsync(id);
+            return res.IsSuccess
+                ? Result<EquipmentDto>.Success(res.Data.ToDto())
+                : Result<EquipmentDto>.Error(res.Msg);
         }
 
         /// <summary>
         /// 新增设备
         /// </summary>
-        /// <param name="entity">设备实体</param>
+        /// <param name="dto">设备 DTO（IsDel/CreateTime 等服务端字段不接受入参）</param>
         [HttpPost]
-        public async Task<Result<bool>> Add([FromBody] EquipmentEntity entity)
+        public async Task<Result<bool>> Add([FromBody] EquipmentDto dto)
         {
-            return await _equipmentService.InsertAsync(entity);
+            return await _equipmentService.InsertAsync(dto.ToEntity());
         }
 
         /// <summary>
         /// 修改设备
         /// </summary>
-        /// <param name="id">设备主键 Id</param>
-        /// <param name="entity">设备实体</param>
+        /// <param name="id">设备主键 Id（以路由参数为准，忽略请求体中的 Id）</param>
+        /// <param name="dto">设备 DTO（IsDel/CreateTime 等服务端字段不接受入参）</param>
         [HttpPut("{id}")]
-        public async Task<Result<bool>> Update(long id, [FromBody] EquipmentEntity entity)
+        public async Task<Result<bool>> Update(long id, [FromBody] EquipmentDto dto)
         {
+            var entity = dto.ToEntity();
             entity.Id = id;
             return await _equipmentService.UpdateAsync(entity);
         }
@@ -96,11 +113,11 @@ namespace IOT_API.Controllers.Asset
         /// 变更设备状态（同步记录状态变更历史）
         /// </summary>
         /// <param name="id">设备主键 Id</param>
-        /// <param name="request">状态变更请求</param>
+        /// <param name="dto">状态变更请求（目标状态/操作人/备注）</param>
         [HttpPost("{id}/status")]
-        public async Task<Result<bool>> ChangeStatus(long id, [FromBody] ChangeStatusRequest request)
+        public async Task<Result<bool>> ChangeStatus(long id, [FromBody] EquipmentStatusChangeDto dto)
         {
-            return await _equipmentService.ChangeStatusAsync(id, request.Status, request.Operator, request.Remark);
+            return await _equipmentService.ChangeStatusAsync(id, dto.Status, dto.Operator, dto.Remark);
         }
 
         /// <summary>
@@ -108,30 +125,65 @@ namespace IOT_API.Controllers.Asset
         /// </summary>
         /// <param name="id">设备主键 Id</param>
         [HttpGet("{id}/status-records")]
-        public async Task<Result<List<EquipmentStatusRecordEntity>>> GetStatusRecords(long id)
+        public async Task<Result<List<EquipmentStatusRecordDto>>> GetStatusRecords(long id)
         {
-            return await _equipmentService.GetStatusRecordsAsync(id);
+            var res = await _equipmentService.GetStatusRecordsAsync(id);
+            return res.IsSuccess
+                ? Result<List<EquipmentStatusRecordDto>>.Success(res.Data.ToDtoList())
+                : Result<List<EquipmentStatusRecordDto>>.Error(res.Msg);
+        }
+
+        /// <summary>
+        /// 查询设备附件列表（资产附件管理）
+        /// </summary>
+        /// <param name="id">设备主键 Id</param>
+        [HttpGet("{id}/attachments")]
+        public async Task<Result<List<EquipmentAttachmentDto>>> GetAttachments(long id)
+        {
+            var res = await _attachmentService.GetByEquipmentAsync(id);
+            return res.IsSuccess
+                ? Result<List<EquipmentAttachmentDto>>.Success(res.Data.ToDtoList())
+                : Result<List<EquipmentAttachmentDto>>.Error(res.Msg);
+        }
+
+        /// <summary>
+        /// 上传设备附件（multipart/form-data，文件字段名 file）
+        /// </summary>
+        /// <param name="id">设备主键 Id</param>
+        /// <param name="file">上传的文件</param>
+        /// <param name="fileType">文件类型（1使用说明书/2合格证明/3校准证书/4保养卡/5合同扫描件/6验收照片/99其他）</param>
+        /// <param name="uploader">上传人</param>
+        /// <param name="remark">备注</param>
+        [HttpPost("{id}/attachments")]
+        [RequestSizeLimit(50 * 1024 * 1024)]
+        public async Task<Result<EquipmentAttachmentDto>> UploadAttachment(long id, IFormFile file,
+            [FromForm] AttachmentTypeEnum fileType = AttachmentTypeEnum.Other,
+            [FromForm] string? uploader = null, [FromForm] string? remark = null)
+        {
+            if (file == null || file.Length == 0)
+            {
+                return Result<EquipmentAttachmentDto>.Error("请选择要上传的文件");
+            }
+
+            // wwwroot 不存在时退回运行目录下的 wwwroot（上传时会自动创建）
+            string webRootPath = _webHostEnvironment.WebRootPath
+                ?? Path.Combine(_webHostEnvironment.ContentRootPath, "wwwroot");
+
+            using var stream = file.OpenReadStream();
+            var res = await _attachmentService.UploadAsync(id, stream, file.FileName, file.Length, fileType, uploader, remark, webRootPath);
+            return res.IsSuccess
+                ? Result<EquipmentAttachmentDto>.Success(res.Data.ToDto())
+                : Result<EquipmentAttachmentDto>.Error(res.Msg);
+        }
+
+        /// <summary>
+        /// 删除设备附件
+        /// </summary>
+        /// <param name="attachmentId">附件主键 Id</param>
+        [HttpDelete("attachments/{attachmentId}")]
+        public async Task<Result<bool>> DeleteAttachment(long attachmentId)
+        {
+            return await _attachmentService.DeleteAsync(attachmentId);
         }
     }
-
-    /// <summary>
-    /// 状态变更请求体
-    /// </summary>
-    public class ChangeStatusRequest
-    {
-        /// <summary>
-        /// 目标状态
-        /// </summary>
-        public EquipmentStatusEnum Status { get; set; }
-
-        /// <summary>
-        /// 操作人
-        /// </summary>
-        public string? Operator { get; set; }
-
-        /// <summary>
-        /// 变更原因/备注
-        /// </summary>
-        public string? Remark { get; set; }
-    }
 }
diff --git a/IOT_API/IOT_API.csproj b/IOT_API/IOT_API.csproj
index fe3f0a4..7a92342 100644
--- a/IOT_API/IOT_API.csproj
+++ b/IOT_API/IOT_API.csproj
@@ -17,4 +17,8 @@
     <ProjectReference Include="..\Service\Service.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <Folder Include="Converters\" />
+  </ItemGroup>
+
 </Project>
diff --git a/IOT_API/Program.cs b/IOT_API/Program.cs
index f039c2f..b6aa79c 100644
--- a/IOT_API/Program.cs
+++ b/IOT_API/Program.cs
@@ -38,6 +38,7 @@ namespace WebAPI
                     options.JsonSerializerOptions.NumberHandling = System.Text.Json.Serialization.JsonNumberHandling.AllowReadingFromString;
 
                     options.JsonSerializerOptions.PropertyNamingPolicy = null;
+
                 });
             // 自动注册业务服务（Service.Interface -> Service.Implement）
             builder.Services.AddBusinessServices();
@@ -63,6 +64,9 @@ namespace WebAPI
 
             app.UseAuthorization();
 
+            // 静态文件：设备附件上传后通过 /uploads/... 访问（存储于 wwwroot）
+            app.UseStaticFiles();
+
             app.MapControllers();
 
             app.Run();
diff --git a/Model/Dto/Asset/EquipmentAttachmentDto.cs b/Model/Dto/Asset/EquipmentAttachmentDto.cs
index 3fa65af..94c56e9 100644
--- a/Model/Dto/Asset/EquipmentAttachmentDto.cs
+++ b/Model/Dto/Asset/EquipmentAttachmentDto.cs
@@ -16,8 +16,8 @@ namespace Model.Dto.Asset
         /// <summary>创建时间</summary>
         public DateTime? CreateTime { get; set; }
 
-        /// <summary>设备Id（关联 EquipmentEntity.Id）</summary>
-        public long EquipmentId { get; set; }
+        /// <summary>设备Id（关联 EquipmentEntity.Id，雪花 Id 转 string 防精度丢失）</summary>
+        public string EquipmentId { get; set; }
 
         /// <summary>文件名称</summary>
         public string? FileName { get; set; }
diff --git a/Model/Dto/Asset/EquipmentCategoryDto.cs b/Model/Dto/Asset/EquipmentCategoryDto.cs
index 47aeb69..90cc22d 100644
--- a/Model/Dto/Asset/EquipmentCategoryDto.cs
+++ b/Model/Dto/Asset/EquipmentCategoryDto.cs
@@ -14,8 +14,8 @@ namespace Model.Dto.Asset
         /// <summary>创建时间</summary>
         public DateTime? CreateTime { get; set; }
 
-        /// <summary>父级分类Id（0表示顶级）</summary>
-        public long ParentId { get; set; }
+        /// <summary>父级分类Id（0表示顶级，雪花 Id 转 string 防精度丢失）</summary>
+        public string ParentId { get; set; }
 
         /// <summary>分类名称</summary>
         public string? Name { get; set; }
diff --git a/Model/Dto/Asset/EquipmentDto.cs b/Model/Dto/Asset/EquipmentDto.cs
index 96be2ad..ee1adcb 100644
--- a/Model/Dto/Asset/EquipmentDto.cs
+++ b/Model/Dto/Asset/EquipmentDto.cs
@@ -7,8 +7,8 @@ namespace Model.Dto.Asset
     /// </summary>
     public class EquipmentDto
     {
-        /// <summary>主键 Id（long → string）</summary>
-        public string Id { get; set; }
+        /// <summary>主键 Id（long → string；入参可空，新增时无需传递）</summary>
+        public string? Id { get; set; }
 
         /// <summary>删除状态（0、未删除；1、已删除）</summary>
         public byte IsDel { get; set; }
@@ -22,8 +22,8 @@ namespace Model.Dto.Asset
         /// <summary>设备名称</summary>
         public string? Name { get; set; }
 
-        /// <summary>设备分类Id（关联 EquipmentCategoryEntity.Id）</summary>
-        public long CategoryId { get; set; }
+        /// <summary>设备分类Id（关联 EquipmentCategoryEntity.Id，雪花 Id 转 string 防精度丢失；可空，未分类时为 "0" 或不传）</summary>
+        public string? CategoryId { get; set; }
 
         /// <summary>设备类型</summary>
         public string? Type { get; set; }
diff --git a/Model/Dto/Asset/EquipmentStatusChangeDto.cs b/Model/Dto/Asset/EquipmentStatusChangeDto.cs
new file mode 100644
index 0000000..f107891
--- /dev/null
+++ b/Model/Dto/Asset/EquipmentStatusChangeDto.cs
@@ -0,0 +1,25 @@
+using Model.Entity.Asset;
+
+namespace Model.Dto.Asset
+{
+    /// <summary>
+    /// 设备状态变更请求 DTO（POST api/asset/equipment/{id}/status 入参）
+    /// </summary>
+    public class EquipmentStatusChangeDto
+    {
+        /// <summary>
+        /// 目标状态（必填）
+        /// </summary>
+        public EquipmentStatusEnum Status { get; set; }
+
+        /// <summary>
+        /// 操作人
+        /// </summary>
+        public string? Operator { get; set; }
+
+        /// <summary>
+        /// 变更原因/备注
+        /// </summary>
+        public string? Remark { get; set; }
+    }
+}
diff --git a/Model/Dto/Asset/EquipmentStatusRecordDto.cs b/Model/Dto/Asset/EquipmentStatusRecordDto.cs
index 35da927..35662c9 100644
--- a/Model/Dto/Asset/EquipmentStatusRecordDto.cs
+++ b/Model/Dto/Asset/EquipmentStatusRecordDto.cs
@@ -16,8 +16,8 @@ namespace Model.Dto.Asset
         /// <summary>创建时间</summary>
         public DateTime? CreateTime { get; set; }
 
-        /// <summary>设备Id（关联 EquipmentEntity.Id）</summary>
-        public long EquipmentId { get; set; }
+        /// <summary>设备Id（关联 EquipmentEntity.Id，雪花 Id 转 string 防精度丢失）</summary>
+        public string EquipmentId { get; set; }
 
         /// <summary>变更前状态</summary>
         public EquipmentStatusEnum FromStatus { get; set; }
diff --git a/Model/Entity/Asset/EquipmentAttachmentEntity.cs b/Model/Entity/Asset/EquipmentAttachmentEntity.cs
index e8a528f..000a4fe 100644
--- a/Model/Entity/Asset/EquipmentAttachmentEntity.cs
+++ b/Model/Entity/Asset/EquipmentAttachmentEntity.cs
@@ -15,7 +15,7 @@ namespace Model.Entity.Asset
         /// <summary>
         /// 文件名称
         /// </summary>
-        [SugarColumn(Length = 200)]
+        [SugarColumn(Length = 200, IsNullable = true)]
         public string? FileName { get; set; }
 
         /// <summary>
@@ -26,13 +26,13 @@ namespace Model.Entity.Asset
         /// <summary>
         /// 文件扩展名（如 .pdf、.jpg）
         /// </summary>
-        [SugarColumn(Length = 20)]
+        [SugarColumn(Length = 20, IsNullable = true)]
         public string? FileExt { get; set; }
 
         /// <summary>
         /// 文件存储地址（上传后存储的相对路径）
         /// </summary>
-        [SugarColumn(Length = 200)]
+        [SugarColumn(Length = 200, IsNullable = true)]
         public string? FileUrl { get; set; }
 
         /// <summary>
@@ -43,13 +43,13 @@ namespace Model.Entity.Asset
         /// <summary>
         /// 上传人
         /// </summary>
-        [SugarColumn(Length = 50)]
+        [SugarColumn(Length = 50, IsNullable = true)]
         public string? Uploader { get; set; }
 
         /// <summary>
         /// 备注
         /// </summary>
-        [SugarColumn(Length = 500)]
+        [SugarColumn(Length = 500, IsNullable = true)]
         public string? Remark { get; set; }
     }
 }
diff --git a/Model/Entity/Asset/EquipmentCategoryEntity.cs b/Model/Entity/Asset/EquipmentCategoryEntity.cs
index 9c7aaab..c34105b 100644
--- a/Model/Entity/Asset/EquipmentCategoryEntity.cs
+++ b/Model/Entity/Asset/EquipmentCategoryEntity.cs
@@ -15,13 +15,13 @@ namespace Model.Entity.Asset
         /// <summary>
         /// 分类名称
         /// </summary>
-        [SugarColumn(Length = 100)]
+        [SugarColumn(Length = 100, IsNullable = true)]
         public string? Name { get; set; }
 
         /// <summary>
         /// 分类编码
         /// </summary>
-        [SugarColumn(Length = 50)]
+        [SugarColumn(Length = 50, IsNullable = true)]
         public string? Code { get; set; }
 
         /// <summary>
@@ -37,7 +37,7 @@ namespace Model.Entity.Asset
         /// <summary>
         /// 备注
         /// </summary>
-        [SugarColumn(Length = 500)]
+        [SugarColumn(Length = 500, IsNullable = true)]
         public string? Remark { get; set; }
     }
 }
diff --git a/Model/Entity/Asset/EquipmentEntity.cs b/Model/Entity/Asset/EquipmentEntity.cs
index 0c96c3f..c54eff4 100644
--- a/Model/Entity/Asset/EquipmentEntity.cs
+++ b/Model/Entity/Asset/EquipmentEntity.cs
@@ -11,13 +11,13 @@ namespace Model.Entity.Asset
         /// <summary>
         /// 设备编号（唯一）
         /// </summary>
-        [SugarColumn(Length = 50)]
+        [SugarColumn(Length = 50, IsNullable = true)]
         public string? Code { get; set; }
 
         /// <summary>
         /// 设备名称
         /// </summary>
-        [SugarColumn(Length = 100)]
+        [SugarColumn(Length = 100, IsNullable = true)]
         public string? Name { get; set; }
 
         /// <summary>
@@ -28,55 +28,55 @@ namespace Model.Entity.Asset
         /// <summary>
         /// 设备类型（实验室/楼层/部门/位置/产品/自定义等分类维度下的类型名称，冗余便于展示）
         /// </summary>
-        [SugarColumn(Length = 100)]
+        [SugarColumn(Length = 100, IsNullable = true)]
         public string? Type { get; set; }
 
         /// <summary>
         /// 设备品牌
         /// </summary>
-        [SugarColumn(Length = 100)]
+        [SugarColumn(Length = 100, IsNullable = true)]
         public string? Brand { get; set; }
 
         /// <summary>
         /// 设备型号
         /// </summary>
-        [SugarColumn(Length = 100)]
+        [SugarColumn(Length = 100, IsNullable = true)]
         public string? Model { get; set; }
 
         /// <summary>
         /// 规格参数
         /// </summary>
-        [SugarColumn(Length = 200)]
+        [SugarColumn(Length = 200, IsNullable = true)]
         public string? Specifications { get; set; }
 
         /// <summary>
         /// 制造商（设备制造商）
         /// </summary>
-        [SugarColumn(Length = 100)]
+        [SugarColumn(Length = 100, IsNullable = true)]
         public string? Manufacturer { get; set; }
 
         /// <summary>
         /// 供应商（资产供应商）
         /// </summary>
-        [SugarColumn(Length = 100)]
+        [SugarColumn(Length = 100, IsNullable = true)]
         public string? Supplier { get; set; }
 
         /// <summary>
         /// 设备图片地址（图片上传后存储的相对路径）
         /// </summary>
-        [SugarColumn(Length = 200)]
+        [SugarColumn(Length = 200, IsNullable = true)]
         public string? ImageUrl { get; set; }
 
         /// <summary>
         /// 二维码编号（一物一码）
         /// </summary>
-        [SugarColumn(Length = 50)]
+        [SugarColumn(Length = 50, IsNullable = true)]
         public string? QrCode { get; set; }
 
         /// <summary>
         /// 设备描述
         /// </summary>
-        [SugarColumn(ColumnDataType = "text")]
+        [SugarColumn(ColumnDataType = "text", IsNullable = true)]
         public string? Description { get; set; }
         #endregion
 
@@ -84,31 +84,31 @@ namespace Model.Entity.Asset
         /// <summary>
         /// 使用部门名称（资产使用部门）
         /// </summary>
-        [SugarColumn(Length = 100)]
+        [SugarColumn(Length = 100, IsNullable = true)]
         public string? Department { get; set; }
 
         /// <summary>
         /// 存放位置（实验室/楼层/房间等位置信息）
         /// </summary>
-        [SugarColumn(Length = 200)]
+        [SugarColumn(Length = 200, IsNullable = true)]
         public string? Location { get; set; }
 
         /// <summary>
         /// 责任人（资产责任人）
         /// </summary>
-        [SugarColumn(Length = 50)]
+        [SugarColumn(Length = 50, IsNullable = true)]
         public string? ResponsiblePerson { get; set; }
 
         /// <summary>
         /// 责任人联系电话（资产责任人电话）
         /// </summary>
-        [SugarColumn(Length = 30)]
+        [SugarColumn(Length = 30, IsNullable = true)]
         public string? ContactPhone { get; set; }
 
         /// <summary>
         /// 保管人
         /// </summary>
-        [SugarColumn(Length = 50)]
+        [SugarColumn(Length = 50, IsNullable = true)]
         public string? Custodian { get; set; }
         #endregion
 
@@ -116,17 +116,19 @@ namespace Model.Entity.Asset
         /// <summary>
         /// 购置日期
         /// </summary>
+        [SugarColumn(IsNullable = true)]
         public DateTime? PurchaseDate { get; set; }
 
         /// <summary>
         /// 购置价格（资产购置价格）
         /// </summary>
-        [SugarColumn(DecimalDigits = 2, Length = 18)]
+        [SugarColumn(DecimalDigits = 2, Length = 18, IsNullable = true)]
         public decimal? PurchasePrice { get; set; }
 
         /// <summary>
         /// 保修到期日期（资产保修到期）
         /// </summary>
+        [SugarColumn(IsNullable = true)]
         public DateTime? WarrantyExpireDate { get; set; }
         #endregion
 
@@ -134,21 +136,25 @@ namespace Model.Entity.Asset
         /// <summary>
         /// 验收日期（资产验收日期）
         /// </summary>
+        [SugarColumn(IsNullable = true)]
         public DateTime? AcceptanceDate { get; set; }
 
         /// <summary>
         /// 启用日期（资产启用日期）
         /// </summary>
+        [SugarColumn(IsNullable = true)]
         public DateTime? EnableDate { get; set; }
 
         /// <summary>
         /// 使用年限（资产使用年限，单位：年）
         /// </summary>
+        [SugarColumn(IsNullable = true)]
         public int? ServiceLifeYears { get; set; }
 
         /// <summary>
         /// 报废日期（资产报废日期）
         /// </summary>
+        [SugarColumn(IsNullable = true)]
         public DateTime? ScrapDate { get; set; }
         #endregion
 
@@ -168,21 +174,25 @@ namespace Model.Entity.Asset
         /// <summary>
         /// 上次校准日期（校准日期）
         /// </summary>
+        [SugarColumn(IsNullable = true)]
         public DateTime? LastCalibrationDate { get; set; }
 
         /// <summary>
         /// 下次校准到期日期（用于判断是否超期）
         /// </summary>
+        [SugarColumn(IsNullable = true)]
         public DateTime? NextCalibrationDate { get; set; }
 
         /// <summary>
         /// 检定日期
         /// </summary>
+        [SugarColumn(IsNullable = true)]
         public DateTime? InspectionDate { get; set; }
 
         /// <summary>
         /// 下次检定到期日期（用于判断是否超期）
         /// </summary>
+        [SugarColumn(IsNullable = true)]
         public DateTime? NextInspectionDate { get; set; }
 
         /// <summary>
@@ -193,11 +203,13 @@ namespace Model.Entity.Asset
         /// <summary>
         /// 上次保养日期（保养日期）
         /// </summary>
+        [SugarColumn(IsNullable = true)]
         public DateTime? LastMaintenanceDate { get; set; }
 
         /// <summary>
         /// 下次保养到期日期（保养周期到期，用于判断是否超期）
         /// </summary>
+        [SugarColumn(IsNullable = true)]
         public DateTime? NextMaintenanceDate { get; set; }
         #endregion
 
@@ -205,24 +217,25 @@ namespace Model.Entity.Asset
         /// <summary>
         /// 备注
         /// </summary>
-        [SugarColumn(Length = 500)]
+        [SugarColumn(Length = 500, IsNullable = true)]
         public string? Remark { get; set; }
 
         /// <summary>
         /// 创建人
         /// </summary>
-        [SugarColumn(Length = 50)]
+        [SugarColumn(Length = 50, IsNullable = true)]
         public string? CreateBy { get; set; }
 
         /// <summary>
         /// 更新人（修改人）
         /// </summary>
-        [SugarColumn(Length = 50)]
+        [SugarColumn(Length = 50, IsNullable = true)]
         public string? UpdateBy { get; set; }
 
         /// <summary>
         /// 更新时间（修改时间）
         /// </summary>
+        [SugarColumn(IsNullable = true)]
         public DateTime? UpdateTime { get; set; }
         #endregion
     }
diff --git a/Model/Entity/Asset/EquipmentStatusRecordEntity.cs b/Model/Entity/Asset/EquipmentStatusRecordEntity.cs
index f752229..a6065c5 100644
--- a/Model/Entity/Asset/EquipmentStatusRecordEntity.cs
+++ b/Model/Entity/Asset/EquipmentStatusRecordEntity.cs
@@ -30,13 +30,13 @@ namespace Model.Entity.Asset
         /// <summary>
         /// 操作人
         /// </summary>
-        [SugarColumn(Length = 50)]
+        [SugarColumn(Length = 50, IsNullable = true)]
         public string? Operator { get; set; }
 
         /// <summary>
         /// 变更原因/备注
         /// </summary>
-        [SugarColumn(Length = 500)]
+        [SugarColumn(Length = 500, IsNullable = true)]
         public string? Remark { get; set; }
     }
 }
diff --git a/Model/Mapper/EntityMapper.cs b/Model/Mapper/EntityMapper.cs
index ea077dc..7ae9310 100644
--- a/Model/Mapper/EntityMapper.cs
+++ b/Model/Mapper/EntityMapper.cs
@@ -26,7 +26,7 @@ namespace Model.Mapper
                 CreateTime = entity.CreateTime,
                 Code = entity.Code,
                 Name = entity.Name,
-                CategoryId = entity.CategoryId,
+                CategoryId = entity.CategoryId.ToString(),
                 Type = entity.Type,
                 Brand = entity.Brand,
                 Model = entity.Model,
@@ -71,6 +71,54 @@ namespace Model.Mapper
         {
             return entities?.Select(e => e.ToDto()).ToList() ?? new List<EquipmentDto>();
         }
+
+        /// <summary>
+        /// EquipmentDto → EquipmentEntity（入参映射，用于新增/修改）
+        /// 安全约定：IsDel/CreateTime/UpdateTime 等服务端管控字段刻意不映射，防止过度绑定（over-binding）；
+        /// Id 解析失败时为 0（新增时由雪花算法自动生成）
+        /// </summary>
+        public static EquipmentEntity ToEntity(this EquipmentDto dto)
+        {
+            if (dto == null) return null;
+            return new EquipmentEntity
+            {
+                Id = long.TryParse(dto.Id, out var id) ? id : 0,
+                Code = dto.Code,
+                Name = dto.Name,
+                CategoryId = long.TryParse(dto.CategoryId, out var categoryId) ? categoryId : 0,
+                Type = dto.Type,
+                Brand = dto.Brand,
+                Model = dto.Model,
+                Specifications = dto.Specifications,
+                Manufacturer = dto.Manufacturer,
+                Supplier = dto.Supplier,
+                ImageUrl = dto.ImageUrl,
+                QrCode = dto.QrCode,
+                Description = dto.Description,
+                Department = dto.Department,
+                Location = dto.Location,
+                ResponsiblePerson = dto.ResponsiblePerson,
+                ContactPhone = dto.ContactPhone,
+                Custodian = dto.Custodian,
+                PurchaseDate = dto.PurchaseDate,
+                PurchasePrice = dto.PurchasePrice,
+                WarrantyExpireDate = dto.WarrantyExpireDate,
+                AcceptanceDate = dto.AcceptanceDate,
+                EnableDate = dto.EnableDate,
+                ServiceLifeYears = dto.ServiceLifeYears,
+                ScrapDate = dto.ScrapDate,
+                Status = dto.Status,
+                CalibrationStatus = dto.CalibrationStatus,
+                LastCalibrationDate = dto.LastCalibrationDate,
+                NextCalibrationDate = dto.NextCalibrationDate,
+                InspectionDate = dto.InspectionDate,
+                NextInspectionDate = dto.NextInspectionDate,
+                MaintenanceStatus = dto.MaintenanceStatus,
+                LastMaintenanceDate = dto.LastMaintenanceDate,
+                NextMaintenanceDate = dto.NextMaintenanceDate,
+                Remark = dto.Remark
+            };
+        }
         #endregion
 
         #region 设备附件
@@ -85,7 +133,7 @@ namespace Model.Mapper
                 Id = entity.Id.ToString(),
                 IsDel = entity.IsDel,
                 CreateTime = entity.CreateTime,
-                EquipmentId = entity.EquipmentId,
+                EquipmentId = entity.EquipmentId.ToString(),
                 FileName = entity.FileName,
                 FileType = entity.FileType,
                 FileExt = entity.FileExt,
@@ -117,7 +165,7 @@ namespace Model.Mapper
                 Id = entity.Id.ToString(),
                 IsDel = entity.IsDel,
                 CreateTime = entity.CreateTime,
-                ParentId = entity.ParentId,
+                ParentId = entity.ParentId.ToString(),
                 Name = entity.Name,
                 Code = entity.Code,
                 Level = entity.Level,
@@ -147,7 +195,7 @@ namespace Model.Mapper
                 Id = entity.Id.ToString(),
                 IsDel = entity.IsDel,
                 CreateTime = entity.CreateTime,
-                EquipmentId = entity.EquipmentId,
+                EquipmentId = entity.EquipmentId.ToString(),
                 FromStatus = entity.FromStatus,
                 ToStatus = entity.ToStatus,
                 ChangeTime = entity.ChangeTime,
diff --git a/Service/Implement/Asset/EquipmentAttachmentService.cs b/Service/Implement/Asset/EquipmentAttachmentService.cs
new file mode 100644
index 0000000..1574967
--- /dev/null
+++ b/Service/Implement/Asset/EquipmentAttachmentService.cs
@@ -0,0 +1,148 @@
+using Model;
+using Model.Entity.Asset;
+using ORM;
+using Service.Interface;
+using SqlSugar;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Threading.Tasks;
+
+namespace Service.Implement
+{
+    /// <summary>
+    /// 设备附件服务实现（资产附件管理）
+    /// </summary>
+    public class EquipmentAttachmentService : IEquipmentAttachmentService
+    {
+        private readonly SqlSugarRepository<EquipmentAttachmentEntity> _repository;
+
+        public EquipmentAttachmentService(SqlSugarRepository<EquipmentAttachmentEntity> repository)
+        {
+            _repository = repository;
+        }
+
+        /// <summary>
+        /// 查询指定设备的附件列表（按上传时间倒序）
+        /// </summary>
+        public async Task<Result<List<EquipmentAttachmentEntity>>> GetByEquipmentAsync(long equipmentId)
+        {
+            try
+            {
+                var list = await _repository.Entities
+                                            .Where(x => x.EquipmentId == equipmentId && x.IsDel == 0)
+                                            .OrderBy(x => x.CreateTime, OrderByType.Desc)
+                                            .ToListAsync();
+                return Result<List<EquipmentAttachmentEntity>>.Success(list);
+            }
+            catch (Exception ex)
+            {
+                return Result<List<EquipmentAttachmentEntity>>.Error("查询附件列表失败", ex);
+            }
+        }
+
+        /// <summary>
+        /// 上传附件（保存文件到 uploads 目录并写入附件记录）
+        /// </summary>
+        public async Task<Result<EquipmentAttachmentEntity>> UploadAsync(long equipmentId, Stream stream, string originalFileName, long fileSize,
+            AttachmentTypeEnum fileType, string? uploader, string? remark, string webRootPath)
+        {
+            if (equipmentId <= 0)
+            {
+                return Result<EquipmentAttachmentEntity>.Error("设备 Id 无效");
+            }
+            if (stream == null || fileSize <= 0)
+            {
+                return Result<EquipmentAttachmentEntity>.Error("上传文件为空");
+            }
+
+            try
+            {
+                // 按设备分目录存储：uploads/equipment/{equipmentId}/
+                string relativeDir = Path.Combine("uploads", "equipment", equipmentId.ToString());
+                string physicalDir = Path.Combine(webRootPath, relativeDir);
+                if (!Directory.Exists(physicalDir))
+                {
+                    Directory.CreateDirectory(physicalDir);
+                }
+
+                // 存储文件名：时间戳 + 原扩展名，避免重名与中文路径问题
+                string ext = Path.GetExtension(originalFileName);
+                string storedName = $"{DateTime.Now:yyyyMMddHHmmssfff}{ext}";
+                string physicalPath = Path.Combine(physicalDir, storedName);
+
+                using (var fileStream = new FileStream(physicalPath, FileMode.Create))
+                {
+                    await stream.CopyToAsync(fileStream);
+                }
+
+                var entity = new EquipmentAttachmentEntity
+                {
+                    EquipmentId = equipmentId,
+                    FileName = originalFileName,
+                    FileType = fileType,
+                    FileExt = ext,
+                    FileUrl = $"/{relativeDir.Replace('\\', '/')}/{storedName}",
+                    FileSize = fileSize,
+                    Uploader = uploader,
+                    Remark = remark,
+                    CreateTime = DateTime.Now
+                };
+
+                await _repository.Context.Insertable(entity).ExecuteCommandAsync();
+                return Result<EquipmentAttachmentEntity>.Success(entity);
+            }
+            catch (Exception ex)
+            {
+                return Result<EquipmentAttachmentEntity>.Error("上传附件失败", ex);
+            }
+        }
+
+        /// <summary>
+        /// 删除附件（软删除记录并删除物理文件）
+        /// </summary>
+        public async Task<Result<bool>> DeleteAsync(long id)
+        {
+            if (id <= 0)
+            {
+                return Result<bool>.Error("附件 Id 无效");
+            }
+            try
+            {
+                var attachment = await _repository.Entities
+                                                  .Where(x => x.Id == id && x.IsDel == 0)
+                                                  .FirstAsync();
+                if (attachment == null)
+                {
+                    return Result<bool>.Error("附件不存在或已被删除");
+                }
+
+                var result = await _repository.Context.Updateable<EquipmentAttachmentEntity>()
+                                              .SetColumns(x => x.IsDel == 1)
+                                              .Where(x => x.Id == id)
+                                              .ExecuteCommandAsync();
+
+                // 删除物理文件（失败不影响记录删除结果）
+                try
+                {
+                    string webRoot = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "wwwroot");
+                    string physicalPath = Path.Combine(webRoot, (attachment.FileUrl ?? string.Empty).TrimStart('/').Replace('/', Path.DirectorySeparatorChar));
+                    if (File.Exists(physicalPath))
+                    {
+                        File.Delete(physicalPath);
+                    }
+                }
+                catch
+                {
+                    // 物理文件删除失败忽略
+                }
+
+                return Result<bool>.Success(result > 0);
+            }
+            catch (Exception ex)
+            {
+                return Result<bool>.Error("删除附件失败", ex);
+            }
+        }
+    }
+}
diff --git a/Service/Interface/Asset/IEquipmentAttachmentService.cs b/Service/Interface/Asset/IEquipmentAttachmentService.cs
new file mode 100644
index 0000000..5cc30a1
--- /dev/null
+++ b/Service/Interface/Asset/IEquipmentAttachmentService.cs
@@ -0,0 +1,43 @@
+using Model;
+using Model.Entity.Asset;
+using System.Collections.Generic;
+using System.IO;
+using System.Threading.Tasks;
+
+namespace Service.Interface
+{
+    /// <summary>
+    /// 设备附件服务接口（资产附件管理：分类存储、在线预览）
+    /// </summary>
+    public interface IEquipmentAttachmentService
+    {
+        /// <summary>
+        /// 查询指定设备的附件列表（按上传时间倒序）
+        /// </summary>
+        /// <param name="equipmentId">设备 Id</param>
+        /// <returns>返回包含附件列表的 Result</returns>
+        Task<Result<List<EquipmentAttachmentEntity>>> GetByEquipmentAsync(long equipmentId);
+
+        /// <summary>
+        /// 上传附件（保存文件到 uploads 目录并写入附件记录）
+        /// </summary>
+        /// <param name="equipmentId">设备 Id</param>
+        /// <param name="stream">文件流</param>
+        /// <param name="originalFileName">原始文件名</param>
+        /// <param name="fileSize">文件大小（字节）</param>
+        /// <param name="fileType">文件类型（说明书/合格证/校准证书等）</param>
+        /// <param name="uploader">上传人</param>
+        /// <param name="remark">备注</param>
+        /// <param name="webRootPath">站点静态文件根目录物理路径</param>
+        /// <returns>返回新增附件记录的 Result</returns>
+        Task<Result<EquipmentAttachmentEntity>> UploadAsync(long equipmentId, Stream stream, string originalFileName, long fileSize,
+            AttachmentTypeEnum fileType, string? uploader, string? remark, string webRootPath);
+
+        /// <summary>
+        /// 删除附件（软删除记录并删除物理文件）
+        /// </summary>
+        /// <param name="id">附件 Id</param>
+        /// <returns>返回操作是否成功的 Result</returns>
+        Task<Result<bool>> DeleteAsync(long id);
+    }
+}