diff --git a/backend/src/main/java/com/senmesh/sfile/service/impl/TransferUserFileServiceImpl.java b/backend/src/main/java/com/senmesh/sfile/service/impl/TransferUserFileServiceImpl.java
index ac1dc3d..e4fc396 100644
--- a/backend/src/main/java/com/senmesh/sfile/service/impl/TransferUserFileServiceImpl.java
+++ b/backend/src/main/java/com/senmesh/sfile/service/impl/TransferUserFileServiceImpl.java
@@ -1,5 +1,6 @@
 package com.senmesh.sfile.service.impl;
 
+import com.google.common.collect.ImmutableSet;
 import com.senmesh.common.exception.util.Assert;
 import com.senmesh.common.util.JsonUtils;
 import com.senmesh.common.util.UserContextHolder;
@@ -32,6 +33,9 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.List;
+import java.util.Locale;
+import java.util.Set;
+import java.util.zip.Deflater;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipOutputStream;
 
@@ -45,6 +49,14 @@ public class TransferUserFileServiceImpl implements TransferUserFileService {
   /** 传输目录多为 bind mount，单次 syscall 成本可达毫秒级，小缓冲会把耗时放大数十倍 */
   private static final int TRANSFER_BUFFER_SIZE = 64 * 1024;
 
+  /** 本身已压缩的格式再跑一遍 deflate 压缩率接近 0，但 CPU 照样全量消耗，故存原样。清单从严，只收确定已压缩的 */
+  private static final Set<String> PRE_COMPRESSED_SUFFIXES = ImmutableSet.of(
+      "zip", "rar", "7z", "gz", "tgz", "bz2", "xz", "jar", "war", "apk",
+      "docx", "xlsx", "pptx", "odt", "ods", "odp", "vsdx",
+      "jpg", "jpeg", "png", "gif", "webp",
+      "mp4", "avi", "mkv", "mov", "wmv", "flv", "mpg", "mpeg", "webm",
+      "mp3", "aac", "flac", "ogg");
+
   @Autowired
   private UserFileService userFileService;
 
@@ -139,6 +151,9 @@ public class TransferUserFileServiceImpl implements TransferUserFileService {
 
         // 创建 ZipEntry（使用 userFileId 命名）
         String entryName = folderName + "/" + userFileId;
+        zos.setLevel(isPreCompressed(file.getFileName())
+            ? Deflater.NO_COMPRESSION
+            : Deflater.DEFAULT_COMPRESSION);
         ZipEntry zipEntry = new ZipEntry(entryName);
         zos.putNextEntry(zipEntry);
 
@@ -166,6 +181,8 @@ public class TransferUserFileServiceImpl implements TransferUserFileService {
 
       String metadataJson = JsonUtils.toJsonString(metadata);
       ZipEntry metadataEntry = new ZipEntry("transferMetadata.json");
+      // 上一个文件可能把 level 置成了 0，JSON 元数据可压缩，需还原
+      zos.setLevel(Deflater.DEFAULT_COMPRESSION);
       zos.putNextEntry(metadataEntry);
       zos.write(metadataJson.getBytes("UTF-8"));
       zos.closeEntry();
@@ -173,4 +190,15 @@ public class TransferUserFileServiceImpl implements TransferUserFileService {
 
     log.info("传输文件打包完成: {}", finalFilePath);
   }
+
+  private boolean isPreCompressed(String fileName) {
+    if (fileName == null) {
+      return false;
+    }
+    int dot = fileName.lastIndexOf('.');
+    if (dot < 0 || dot == fileName.length() - 1) {
+      return false;
+    }
+    return PRE_COMPRESSED_SUFFIXES.contains(fileName.substring(dot + 1).toLowerCase(Locale.ROOT));
+  }
 }