diff --git a/unipay/providers/wechat.py b/unipay/providers/wechat.py
index 6576059..c5d6274 100644
--- a/unipay/providers/wechat.py
+++ b/unipay/providers/wechat.py
@@ -32,7 +32,7 @@ class WechatGateway(Gateway):
 
 		# 加载私钥
 		self._private_key = serialization.load_pem_private_key(
-			private_key_pem.encode(),
+			private_key_pem,
 			password=None,
 		)