diff --git a/IRaCIS.Core.Application/Service/ImageAndDoc/DTO/DicomInstanceModel.cs b/IRaCIS.Core.Application/Service/ImageAndDoc/DTO/DicomInstanceModel.cs
index a95065a2d..033e402f3 100644
--- a/IRaCIS.Core.Application/Service/ImageAndDoc/DTO/DicomInstanceModel.cs
+++ b/IRaCIS.Core.Application/Service/ImageAndDoc/DTO/DicomInstanceModel.cs
@@ -29,6 +29,9 @@
 
         public string SliceThickness { get; set; } = String.Empty;
 
+        public string ImagePositionPatient { get; set; }
+        public string ImageOrientationPatient { get; set; }
+
     }
 
 
diff --git a/IRaCIS.Core.Application/Service/ImageAndDoc/InstanceService.cs b/IRaCIS.Core.Application/Service/ImageAndDoc/InstanceService.cs
index 0377588bf..7b057c5c8 100644
--- a/IRaCIS.Core.Application/Service/ImageAndDoc/InstanceService.cs
+++ b/IRaCIS.Core.Application/Service/ImageAndDoc/InstanceService.cs
@@ -29,6 +29,14 @@ namespace IRaCIS.Core.Application.Services
                 .OrderBy(s => s.InstanceNumber).ThenBy(s => s.InstanceTime).ThenBy(s => s.CreateTime)
                 .ProjectTo<DicomInstanceDTO>(_mapper.ConfigurationProvider).ToListAsync();
 
+            // ⭐ DICOM 空间排序（带兜底）
+            var sorted = DicomSortHelper.SortSlices(
+                list,
+                x => x.ImagePositionPatient,
+                x => x.ImageOrientationPatient,
+                x => x.InstanceNumber
+            );
+
             var seriesInfo = await _instanceRepository.Where(s => s.SeriesId == seriesId).Select(t => new
             {
                 t.DicomSerie.ImageResizePath,
@@ -38,7 +46,7 @@ namespace IRaCIS.Core.Application.Services
                 t.DicomSerie.SubjectVisit.VisitName
             }).FirstOrDefaultAsync();
 
-            return ResponseOutput.Ok(list, seriesInfo);
+            return ResponseOutput.Ok(sorted, seriesInfo);
         }