diff --git a/hb_server/apps/system/serializers.py b/hb_server/apps/system/serializers.py
index 1ee7375..a8457ff 100644
--- a/hb_server/apps/system/serializers.py
+++ b/hb_server/apps/system/serializers.py
@@ -133,7 +133,7 @@ class UserStandardSerializer(serializers.ModelSerializer):
         fields = ['id', 'username', 'name', 'signature']
     
     def get_signature(self, obj):
-        if obj.employee_user:
+        if hasattr(obj, 'employee_user'):
             return obj.employee_user.signature
         return None
 # class UserStandardSerializer(serializers.ModelSerializer):