diff --git a/weixin/pay.py b/weixin/pay.py
index bbffa0d..0e61253 100644
--- a/weixin/pay.py
+++ b/weixin/pay.py
@@ -75,7 +75,8 @@ def to_xml(self, raw):
 
     def to_dict(self, content):
         raw = {}
-        root = etree.fromstring(content.encode("utf-8"),
+        content = content.encode("utf-8") if isinstance(content,str) else content
+        root = etree.fromstring(content,
                                 parser=etree.XMLParser(resolve_entities=False))
         for child in root:
             raw[child.tag] = child.text