diff --git a/include/configs/outbounds/vless.h b/include/configs/outbounds/vless.h
index 27b63f3..ebe7d0f 100644
--- a/include/configs/outbounds/vless.h
+++ b/include/configs/outbounds/vless.h
@@ -14,7 +14,7 @@ namespace Configs
         QString uuid;
         QString flow;
         std::shared_ptr<TLS> tls = std::make_shared<TLS>();
-        QString packet_encoding;
+        QString packet_encoding = "xudp";
         std::shared_ptr<Multiplex> multiplex = std::make_shared<Multiplex>();
         std::shared_ptr<Transport> transport = std::make_shared<Transport>();
 
diff --git a/include/configs/outbounds/vmess.h b/include/configs/outbounds/vmess.h
index 4320e29..112e98e 100644
--- a/include/configs/outbounds/vmess.h
+++ b/include/configs/outbounds/vmess.h
@@ -19,7 +19,7 @@ namespace Configs
         bool global_padding = false;
         bool authenticated_length = false;
         std::shared_ptr<TLS> tls = std::make_shared<TLS>();
-        QString packet_encoding;
+        QString packet_encoding = "xudp";
         std::shared_ptr<Transport> transport = std::make_shared<Transport>();
         std::shared_ptr<Multiplex> multiplex = std::make_shared<Multiplex>();
 
diff --git a/src/configs/outbounds/vless.cpp b/src/configs/outbounds/vless.cpp
index 7bf3933..f467e53 100644
--- a/src/configs/outbounds/vless.cpp
+++ b/src/configs/outbounds/vless.cpp
@@ -25,7 +25,7 @@ namespace Configs {
             tls->enabled = true;
         }
         
-        packet_encoding = GetQueryValue(query, "packetEncoding", "");
+        packet_encoding = GetQueryValue(query, "packetEncoding", "xudp");
         multiplex->ParseFromLink(link);
 
         return !(uuid.isEmpty() || server.isEmpty());