diff --git a/supwisdom/protocol/webservice.py b/supwisdom/protocol/webservice.py
index 48062b3..99ee4ea 100644
--- a/supwisdom/protocol/webservice.py
+++ b/supwisdom/protocol/webservice.py
@@ -200,5 +200,8 @@
     def _pack_body(self, request):
         funcdata = request.serialize()
         request_token = self.session.gen_request_token()
-        request_token['funcdata'] = funcdata.decode('utf-8', 'ignore')
+        if isinstance(funcdata, unicode):
+            request_token['funcdata'] = funcdata
+        elif isinstance(funcdata, str):
+            request_token['funcdata'] = funcdata.encode('gbk', 'ignore')
         return json.dumps(request_token, ensure_ascii=False)