diff --git a/proxy/plugin/proxy_pool.py b/proxy/plugin/proxy_pool.py
index e701fcb8..3cb664c7 100644
--- a/proxy/plugin/proxy_pool.py
+++ b/proxy/plugin/proxy_pool.py
@@ -79,6 +79,6 @@ class ProxyPoolPlugin(HttpProxyBasePlugin):
             COLON + SLASH + SLASH +
             request.host +
             COLON +
-            bytes(request.port) +
+            str(request.port).encode() +
             request.path
         )