diff --git a/weixin.py b/weixin.py
index 7088558..e3b48e4 100755
--- a/weixin.py
+++ b/weixin.py
@@ -1161,7 +1161,7 @@ class UnicodeStreamFilter:
 
     def write(self, s):
         if type(s) == str:
-            s = s.decode('utf-8')
+            s = s.encode().decode('utf-8')
         s = s.encode(self.encode_to, self.errors).decode(self.encode_to)
         self.target.write(s)