diff --git a/fam-core/src/fam_core/dispatcher/dispatcher.py b/fam-core/src/fam_core/dispatcher/dispatcher.py
index 67849de..81562ab 100644
--- a/fam-core/src/fam_core/dispatcher/dispatcher.py
+++ b/fam-core/src/fam_core/dispatcher/dispatcher.py
@@ -46,6 +46,15 @@ FFMPEG_CANDIDATES = [
 ]
 
 
+def _safe_remove(path):
+    """忽略不存在/清理失败的删除"""
+    try:
+        if os.path.isfile(path):
+            os.remove(path)
+    except OSError:
+        pass
+
+
 class Dispatcher:
     """任务下发器，30s 轮询（异步队列 + 分块断点续传）"""
 
@@ -156,6 +165,11 @@ class Dispatcher:
         src_size = os.path.getsize(video_path)
         start = time.time()
 
+        # 写临时文件（带 PID 防多进程冲突），成功后原子 rename —
+        # 服务被 kill 时 ffmpeg 成为孤儿继续写 tmp，缓存目录中
+        # 只会出现完整产物，杜绝半成品被复用（曾导致上传损坏视频）
+        tmp_path = f"{out_path}.{os.getpid()}.tmp"
+
         cmd = [
             self.ffmpeg, '-y',
             '-i', video_path,
@@ -164,7 +178,7 @@ class Dispatcher:
                      'scale=trunc(iw/2)*2:trunc(ih/2)*2'),
             '-c:v', 'libx264', '-preset', 'veryfast', '-crf', '28',
             '-an',
-            out_path,
+            tmp_path,
         ]
         try:
             result = subprocess.run(
@@ -172,17 +186,21 @@ class Dispatcher:
                 timeout=self.compress_timeout,
             )
         except subprocess.TimeoutExpired:
+            _safe_remove(tmp_path)
             logger.error(f"[task_id={task_id}] 压缩超时 ({self.compress_timeout}s)，回退原始上传")
             return None
         except OSError as e:
             logger.error(f"[task_id={task_id}] 启动 ffmpeg 失败: {e}")
             return None
 
-        if result.returncode != 0 or not os.path.isfile(out_path) or os.path.getsize(out_path) == 0:
+        if result.returncode != 0 or not os.path.isfile(tmp_path) or os.path.getsize(tmp_path) == 0:
+            _safe_remove(tmp_path)
             stderr_tail = (result.stderr or '')[-300:]
             logger.error(f"[task_id={task_id}] 压缩失败 (rc={result.returncode}): {stderr_tail}")
             return None
 
+        os.replace(tmp_path, out_path)
+
         dst_size = os.path.getsize(out_path)
         elapsed = time.time() - start
         logger.info(f"[task_id={task_id}] 预压缩完成: {src_size/1048576:.1f}MB → "
@@ -191,7 +209,7 @@ class Dispatcher:
 
     @staticmethod
     def _cleanup_compress_cache():
-        """清理超过 TTL 的压缩缓存目录（tmpfs 空间有限）"""
+        """清理超过 TTL 的压缩缓存目录 + 孤儿 .tmp 残留（tmpfs 空间有限）"""
         try:
             if not os.path.isdir(COMPRESS_DIR):
                 return
@@ -199,8 +217,15 @@ class Dispatcher:
             for entry in os.listdir(COMPRESS_DIR):
                 path = os.path.join(COMPRESS_DIR, entry)
                 try:
-                    if os.path.isdir(path) and os.path.getmtime(path) < cutoff:
-                        shutil.rmtree(path, ignore_errors=True)
+                    if os.path.isdir(path):
+                        if os.path.getmtime(path) < cutoff:
+                            shutil.rmtree(path, ignore_errors=True)
+                            continue
+                        # 清理超过 1h 的 .tmp 残留（孤儿 ffmpeg 产物）
+                        for fn in os.listdir(path):
+                            if fn.endswith('.tmp') and \
+                                    os.path.getmtime(os.path.join(path, fn)) < time.time() - 3600:
+                                _safe_remove(os.path.join(path, fn))
                 except OSError:
                     continue
         except OSError: