diff --git a/supwisdom/protocol/webservice.py b/supwisdom/protocol/webservice.py
index 99ee4ea..657fc68 100644
--- a/supwisdom/protocol/webservice.py
+++ b/supwisdom/protocol/webservice.py
@@ -203,5 +203,5 @@
         if isinstance(funcdata, unicode):
             request_token['funcdata'] = funcdata
         elif isinstance(funcdata, str):
-            request_token['funcdata'] = funcdata.encode('gbk', 'ignore')
+            request_token['funcdata'] = funcdata.decode('gbk', 'ignore')
         return json.dumps(request_token, ensure_ascii=False)