diff --git a/README.md b/README.md
index c8cc436..8032fc6 100644
--- a/README.md
+++ b/README.md
@@ -15,6 +15,7 @@ A simple VPN written in golang.
 * VPN over websocket
 * VPN over tls
 * VPN over quic
+* VPN over grpc
 
 # Usage
 
@@ -45,7 +46,7 @@ Usage of ./vtun:
   -obfs
         enable data obfuscation
   -p string
-        protocol tcp/udp/tls/quic/ws/wss (default "wss")
+        protocol tcp/udp/tls/quic/grpc/ws/wss (default "wss")
   -path string
         websocket path (default "/freedom")
   -s string
diff --git a/README_CN.md b/README_CN.md
index 0933432..51279b1 100644
--- a/README_CN.md
+++ b/README_CN.md
@@ -15,6 +15,7 @@
 * 支持websocket
 * 支持tls
 * 支持quic
+* 支持grpc
 
 # 用法
 
@@ -45,7 +46,7 @@ Usage of ./vtun:
   -obfs
         enable data obfuscation
   -p string
-        protocol tcp/udp/tls/quic/ws/wss (default "wss")
+        protocol tcp/udp/tls/quic/grpc/ws/wss (default "wss")
   -path string
         websocket path (default "/freedom")
   -s string
diff --git a/main.go b/main.go
index 3bd56be..5086d3d 100644
--- a/main.go
+++ b/main.go
@@ -33,7 +33,7 @@ func main() {
 	flag.StringVar(&config.IntranetServerIPv6, "sip6", "fced:9999::1", "intranet server ipv6")
 	flag.StringVar(&config.DNSServerIP, "dip", "8.8.8.8", "dns server ip")
 	flag.StringVar(&config.Key, "k", "freedom@2022", "key")
-	flag.StringVar(&config.Protocol, "p", "wss", "protocol tcp/udp/tls/quic/ws/wss")
+	flag.StringVar(&config.Protocol, "p", "wss", "protocol tcp/udp/tls/quic/grpc/ws/wss")
 	flag.StringVar(&config.WebSocketPath, "path", "/freedom", "websocket path")
 	flag.BoolVar(&config.ServerMode, "S", false, "server mode")
 	flag.BoolVar(&config.GlobalMode, "g", false, "client global mode")