diff --git a/apps/worker/video_processing/pip_engine.py b/apps/worker/video_processing/pip_engine.py
index 050a25f42..cb84550e3 100755
--- a/apps/worker/video_processing/pip_engine.py
+++ b/apps/worker/video_processing/pip_engine.py
@@ -179,7 +179,7 @@ class PiPConfig:
                 logger.warning("PiP图层解析失败，跳过: %s", e)
 
         # 按 z_index 排序
-        layers.sort(key=lambda l: l.z_index)
+        layers.sort(key=lambda layer: layer.z_index)
 
         return cls(enabled=bool(layers), layers=layers)