diff --git a/IRC.Core.SCP/Service/CStoreSCPService.cs b/IRC.Core.SCP/Service/CStoreSCPService.cs
index 11270659d..1ce3063b9 100644
--- a/IRC.Core.SCP/Service/CStoreSCPService.cs
+++ b/IRC.Core.SCP/Service/CStoreSCPService.cs
@@ -503,7 +503,7 @@ namespace IRaCIS.Core.SCP.Service
 
                             bot.Add(botOffset);
 
-                            botOffset += (uint)data.Length; // 累加帧长度
+                            botOffset += (uint)data.Length +8 ; // 累加帧长度
 
                             while (offset < data.Length)
                             {
@@ -540,24 +540,28 @@ namespace IRaCIS.Core.SCP.Service
                         dicomFile.Save(ms);
                     }
                     //传递过来的就是拆分的，但是是没有偏移表的，我需要自己创建偏移表，不然生成缩略图失败
-                    else if (syntax.IsEncapsulated && fragmentCount > pixelData.NumberOfFrames && originOffsetTable.Count==0)
+                    else if (syntax.IsEncapsulated && fragmentCount > pixelData.NumberOfFrames && originOffsetTable.Count == 0)
                     {
-                       
+
                         uint offset = 0;
 
                         bot.Add(offset);
 
-                        var fistSize = frag.Fragments.FirstOrDefault()?.Size??0;
+                        var fistSize = frag.Fragments.FirstOrDefault()?.Size ?? 0;
 
                         //和上一个大小不一样
                         var isDiffrentBefore = false;
 
+                        uint count = 0;
+
                         // 假设你知道每帧对应的 fragment 数量
                         foreach (var frameFragments in frag.Fragments)
                         {
-                            if(frameFragments.Size== fistSize)
+                            count++;
+
+                            if (frameFragments.Size == fistSize)
                             {
-                                 isDiffrentBefore = false;
+                                isDiffrentBefore = false;
                                 // 累加这一帧所有 fragment 的大小
                                 offset += (uint)frameFragments.Size;
                                 continue;
@@ -571,7 +575,10 @@ namespace IRaCIS.Core.SCP.Service
 
                             if (isDiffrentBefore)
                             {
+                                //每个Fragment 也占用字节
+                                offset += 8 * count;
                                 bot.Add(offset);
+                                count = 0;
 
                             }
 
diff --git a/IRaCIS.Core.API/Controllers/UploadDownLoadController.cs b/IRaCIS.Core.API/Controllers/UploadDownLoadController.cs
index df3fab776..fd8b29bbf 100644
--- a/IRaCIS.Core.API/Controllers/UploadDownLoadController.cs
+++ b/IRaCIS.Core.API/Controllers/UploadDownLoadController.cs
@@ -894,6 +894,51 @@ namespace IRaCIS.Core.API.Controllers
         #endregion
 
 
+        [HttpGet("download/DownloadBigFileBatch")]
+        [AllowAnonymous]
+        public async Task<IActionResult> DownloadBigFileBatch(string fileName)
+        {
+            Response.ContentType = "application/zip";
+            Response.Headers["Content-Disposition"] = "attachment; filename=big-file.zip";
+            Response.Headers["Cache-Control"] = "no-store";
+
+            // ⚠️ 关键：直接用 Response.Body
+             using var zip = new ZipArchive(Response.Body,ZipArchiveMode.Create,leaveOpen: true);
+
+            // 本地大文件路径
+            var files = new[]
+            {
+                    @$"{fileName}",
+            };
+
+            foreach (var filePath in files)
+            {
+                var phyFilePath = FileStoreHelper.GetPhysicalFilePath(_hostEnvironment, filePath);
+
+                Console.WriteLine(phyFilePath);
+
+                var entryName = Path.GetFileName(phyFilePath);
+
+                var entry = zip.CreateEntry( entryName,
+                    CompressionLevel.Fastest); // 大文件建议 Fastest
+
+                await using var entryStream = entry.Open();
+                await using var fileStream = new FileStream(
+                    filePath,
+                    FileMode.Open,
+                    FileAccess.Read,
+                    FileShare.Read,
+                    bufferSize: 1024 * 64,   // 64KB buffer
+                    useAsync: true);
+
+                await fileStream.CopyToAsync(entryStream);
+            }
+
+            return new EmptyResult(); // 必须
+        }
+
+
+
         [HttpPost("download/PatientStudyBatchDownload")]
         public async Task<IActionResult> DownloadPatientStudyBatch([FromServices] IPatientService _patientService, [FromServices] IOSSService _oSSService,
              [FromServices] IHubContext<DownloadHub, IDownloadClient> _downLoadHub,
@@ -1032,6 +1077,10 @@ namespace IRaCIS.Core.API.Controllers
 
                                     // 获取 Pixel Data 标签
                                     var pixelData = DicomPixelData.Create(dicomFile.Dataset);
+
+                                    var frag = dicomFile.Dataset.GetDicomItem<DicomOtherByteFragment>(DicomTag.PixelData);
+
+                                    var originOffsetTable = frag.OffsetTable;
                                     //获取像素是否为封装形式
                                     var syntax = dicomFile.Dataset.InternalTransferSyntax;
 
@@ -1046,6 +1095,8 @@ namespace IRaCIS.Core.API.Controllers
                                             var frameData = pixelData.GetFrame(n);
                                             newFragments.Fragments.Add(new MemoryByteBuffer(frameData.Data));
                                         }
+
+                                        newFragments.OffsetTable.AddRange(originOffsetTable.ToArray());
                                         // 替换原有的片段序列
                                         dicomFile.Dataset.AddOrUpdate(newFragments);
                                     }