diff --git a/app.go b/app.go
index f6a6c6c..55f92ff 100644
--- a/app.go
+++ b/app.go
@@ -6,6 +6,7 @@ import (
 	"os"
 	"path/filepath"
 	rt "runtime"
+	"sync"
 	"time"
 
 	"github.com/jkstack/anet"
@@ -22,9 +23,10 @@ type app struct {
 	chWrite chan *anet.Msg
 
 	// runtime
-	ctx       context.Context
-	cancel    context.CancelFunc
-	connected bool
+	ctx        context.Context
+	cancel     context.CancelFunc
+	connected  bool
+	mWriteLock sync.Mutex
 
 	// monitor
 	inPackets, inBytes   uint64
diff --git a/app_handler.go b/app_handler.go
index 408b313..6978bb1 100644
--- a/app_handler.go
+++ b/app_handler.go
@@ -61,7 +61,9 @@ func (app *app) write(ctx context.Context, cancel context.CancelFunc, conn *webs
 				return
 			}
 
+			app.mWriteLock.Lock()
 			err = conn.WriteMessage(websocket.TextMessage, data)
+			app.mWriteLock.Unlock()
 			if err != nil {
 				logging.Error("write message: %v", err)
 				return
@@ -89,7 +91,9 @@ func (app *app) keepalive(ctx context.Context, conn *websocket.Conn) {
 		case <-ctx.Done():
 			return
 		case <-tk.C:
+			app.mWriteLock.Lock()
 			conn.WriteControl(websocket.PingMessage, nil, time.Now().Add(2*time.Second))
+			app.mWriteLock.Unlock()
 		}
 	}
 }