diff --git a/x-file-storage-core/src/main/java/org/dromara/x/file/storage/core/upload/CompleteMultipartUploadActuator.java b/x-file-storage-core/src/main/java/org/dromara/x/file/storage/core/upload/CompleteMultipartUploadActuator.java
index dfbec90f81175dd8d6760abe9df30361ce63a664..845142cd80bc2de103274e1e880345d13b917a23 100644
--- a/x-file-storage-core/src/main/java/org/dromara/x/file/storage/core/upload/CompleteMultipartUploadActuator.java
+++ b/x-file-storage-core/src/main/java/org/dromara/x/file/storage/core/upload/CompleteMultipartUploadActuator.java
@@ -52,13 +52,15 @@ public class CompleteMultipartUploadActuator {
                                         fileStorageService.listParts(_fileInfo).listParts(_fileStorage, aspectList);
                                 _pre.setPartInfoList(partInfoList.getList());
                             }
-
+                            // 计算并设置文件总大小
+                            long totalSize = _pre.getPartInfoList().stream().mapToLong(FilePartInfo::getPartSize).sum();
+                            _fileInfo.setSize(totalSize);
                             _fileStorage.completeMultipartUpload(_pre);
                             _fileRecorder.update(_fileInfo);
                             _fileRecorder.deleteFilePartByUploadId(_fileInfo.getUploadId());
 
                             // 文件上传完成，识别文件 ContentType
-                            if (StrUtil.isNotBlank(_fileInfo.getContentType())) {
+                            if (StrUtil.isBlank(_fileInfo.getContentType())) {
                                 try {
                                     new Downloader(_fileInfo, aspectList, _fileStorage, Downloader.TARGET_FILE)
                                             .inputStream(in -> {