diff --git a/docker/entrypoint.sh b/docker/entrypoint.sh
index 6f7869e..5038e21 100644
--- a/docker/entrypoint.sh
+++ b/docker/entrypoint.sh
@@ -50,22 +50,22 @@ main() {
   fi
 
   if [ -n "$MTU" ]; then
-    ARGS="--mtu $MTU"
+    ARGS="-mtu $MTU"
   fi
 
   if [ -n "$STATS" ]; then
-    ARGS="$ARGS --stats $STATS"
+    ARGS="$ARGS -stats $STATS"
   fi
 
   if [ -n "$TOKEN" ]; then
-    ARGS="$ARGS --token $TOKEN"
+    ARGS="$ARGS -token $TOKEN"
   fi
 
   exec tun2socks \
-    --loglevel "$LOGLEVEL" \
-    --fwmark "$FWMARK" \
-    --device "$TUN" \
-    --proxy "$PROXY" \
+    -loglevel "$LOGLEVEL" \
+    -fwmark "$FWMARK" \
+    -device "$TUN" \
+    -proxy "$PROXY" \
     $ARGS
 }
 
diff --git a/engine/engine.go b/engine/engine.go
index d007968..3c21353 100755
--- a/engine/engine.go
+++ b/engine/engine.go
@@ -30,7 +30,7 @@ func Insert(k *Key) {
 }
 
 type Key struct {
-	MTU       uint32
+	MTU       int
 	Mark      int
 	Proxy     string
 	Stats     string
@@ -138,7 +138,7 @@ func (e *engine) setDevice() (err error) {
 		return errors.New("empty device")
 	}
 
-	e.device, err = parseDevice(e.Device, e.MTU)
+	e.device, err = parseDevice(e.Device, uint32(e.MTU))
 	return
 }
 
diff --git a/go.mod b/go.mod
index 50eb1be..0461556 100644
--- a/go.mod
+++ b/go.mod
@@ -10,7 +10,6 @@ require (
 	github.com/gofrs/uuid v4.0.0+incompatible
 	github.com/gorilla/websocket v1.4.2
 	github.com/sirupsen/logrus v1.7.0
-	github.com/spf13/pflag v1.0.5
 	github.com/stretchr/testify v1.5.1
 	go.uber.org/atomic v1.7.0
 	golang.org/x/crypto v0.0.0-20201221181555-eec23a3978ad // indirect
diff --git a/main.go b/main.go
index eb5323a..844345e 100755
--- a/main.go
+++ b/main.go
@@ -1,28 +1,27 @@
 package main
 
 import (
+	"flag"
 	"os"
 	"os/signal"
 	"syscall"
 
 	"github.com/xjasonlyu/tun2socks/engine"
 	"github.com/xjasonlyu/tun2socks/log"
-
-	flag "github.com/spf13/pflag"
 )
 
 var key = new(engine.Key)
 
 func init() {
-	flag.StringVarP(&key.Device, "device", "d", "", "use this device [driver://]name")
-	flag.IntVar(&key.Mark, "fwmark", 0, "set firewall MARK (Linux only)")
-	flag.StringVarP(&key.Interface, "interface", "i", "", "use network INTERFACE (Linux/MacOS only)")
-	flag.StringVarP(&key.LogLevel, "loglevel", "l", "info", "log level [debug|info|warn|error|silent]")
-	flag.Uint32VarP(&key.MTU, "mtu", "m", 0, "set device maximum transmission unit (MTU)")
-	flag.StringVarP(&key.Proxy, "proxy", "p", "", "use this proxy [protocol://]host[:port]")
+	flag.IntVar(&key.Mark, "fwmark", 0, "Set firewall MARK (Linux only)")
+	flag.IntVar(&key.MTU, "mtu", 0, "Set device maximum transmission unit (MTU)")
+	flag.BoolVar(&key.Version, "version", false, "Show version information and quit")
+	flag.StringVar(&key.Device, "device", "", "Use this device [driver://]name")
+	flag.StringVar(&key.Interface, "interface", "", "Use network INTERFACE (Linux/MacOS only)")
+	flag.StringVar(&key.LogLevel, "loglevel", "info", "Log level [debug|info|warn|error|silent]")
+	flag.StringVar(&key.Proxy, "proxy", "", "Use this proxy [protocol://]host[:port]")
 	flag.StringVar(&key.Stats, "stats", "", "HTTP statistic server listen address")
 	flag.StringVar(&key.Token, "token", "", "HTTP statistic server auth token")
-	flag.BoolVarP(&key.Version, "version", "v", false, "show version information and quit")
 	flag.Parse()
 }