diff --git a/apps/wpmw/serializers.py b/apps/wpmw/serializers.py
index 779fd090..482036a2 100644
--- a/apps/wpmw/serializers.py
+++ b/apps/wpmw/serializers.py
@@ -34,7 +34,7 @@ class WprNewSerializer(serializers.Serializer):
 
 class WproutSerializer(serializers.Serializer):
     id = serializers.CharField(label="wprId")
-    number_out = serializers.CharField(label="对外编号")
+    number_out = serializers.CharField(label="对外编号", allow_null=True)
 
 
 class WproutListSerializer(serializers.Serializer):