diff --git a/cmd/client.go b/cmd/client.go
index 4788d4c..2382d72 100644
--- a/cmd/client.go
+++ b/cmd/client.go
@@ -153,7 +153,7 @@ func (c *Client) ping() {
 	c.send("ping")
 }
 
-//Publish -------------------------------------- pub-sub --------------------------------------
+// Publish -------------------------------------- pub-sub --------------------------------------
 func (c *Client) Publish(topic string, message string) error {
 	return c.send("publish", topic, message)
 }
@@ -168,10 +168,12 @@ func (c *Client) Delay(topic string, message string, delay int) error {
 
 /*
 Timer
-func (c *Client) Timer(topic string, expr string, fun func()) {
-	c.timerFun[topic] = fun
-	c.send("timer", topic, expr, "x")
-}*/
+
+	func (c *Client) Timer(topic string, expr string, fun func()) {
+		c.timerFun[topic] = fun
+		c.send("timer", topic, expr, "x")
+	}
+*/
 func (c *Client) Timer(topic string, fun func()) {
 	if fun != nil {
 		c.timerFun[topic] = fun
@@ -195,28 +197,37 @@ func (c *Client) Close() {
 	c.conn.Close()
 }
 
+// TryLock
+func TryLock(key string, duration int) {
+	/*uuid := uuid.New()
+
+	TODO
+
+	return Lock{Key: key, Value: uuid}*/
+}
+
 // Lock Key
 func (c *Client) Lock(key string, duration int) Lock {
-	v := uuid.New()
-	c.send("v", key, v, strconv.Itoa(duration))
+	uuid := uuid.New()
+	c.send("uuid", key, uuid, strconv.Itoa(duration))
 
 	lockChan := make(chan int, 2)
 	go func() {
 		c.wlock.Lock()
 		defer c.wlock.Unlock()
-		c.lockFlag[v] = &Lock{
+		c.lockFlag[uuid] = &Lock{
 			Key:      key,
-			Value:    v,
+			Value:    uuid,
 			flagChan: lockChan,
 		}
 	}()
 
 	select {
 	case <-lockChan:
-		log.Println("v-ok", time.Now().UnixNano()/1e6, v)
+		log.Println("lock-ok", time.Now().UnixNano()/1e6, uuid)
 	}
 
-	return Lock{Key: key, Value: v}
+	return Lock{Key: key, Value: uuid}
 }
 
 func (c *Client) Unlock(l Lock) {
diff --git a/internal/zbus/zbus-message-handler.go b/internal/zbus/zbus-message-handler.go
index d3fe093..10457a5 100644
--- a/internal/zbus/zbus-message-handler.go
+++ b/internal/zbus/zbus-message-handler.go
@@ -203,21 +203,21 @@ func messageHandler(v Message) {
 				}
 				Bus.shutdown()
 			}
-		case "lock":
+		case "lock", "trylock":
 			// lock key uuid 5
 			if len(rcmd) != 4 {
 				c.send("-Error: lock para number![" + strings.Join(rcmd, " ") + "]")
 				return
 			}
 			d, _ := strconv.Atoi(rcmd[3])
-			Bus._lock(&Lock{key: rcmd[1], uuid: rcmd[2], duration: d})
+			Bus._lock(&Lock{cmd: cmd, key: rcmd[1], uuid: rcmd[2], duration: d})
 		case "unlock":
 			// unlock key uuid
 			if len(rcmd) != 3 {
 				c.send("-Error: unlock para number![" + strings.Join(rcmd, " ") + "]")
 				return
 			}
-			Bus._unlock(Lock{key: rcmd[1], uuid: rcmd[2]})
+			Bus._unlock(Lock{cmd: cmd, key: rcmd[1], uuid: rcmd[2]})
 		default:
 			c.send("-Error: default not supported:[" + strings.Join(rcmd, " ") + "]")
 			return
diff --git a/internal/zbus/zbus.go b/internal/zbus/zbus.go
index b0808b4..30064df 100644
--- a/internal/zbus/zbus.go
+++ b/internal/zbus/zbus.go
@@ -95,9 +95,10 @@ type ZConn struct { //ZConn
 }
 
 type Lock struct {
-	key      string
-	uuid     string
-	duration int
+	cmd      string // lock|trylock|unlock
+	key      string // lock key
+	uuid     string // apply for unique identification
+	duration int    // lock duration (seconds)
 	timer    *time.Timer
 	start    int64
 	//stop     time.Time
@@ -432,7 +433,12 @@ func (s *ZBus) _lock(lock *Lock) {
 			}
 		}()
 	} else {
-		s.locks[lock.key] = append(locks, lock)
+		switch lock.cmd {
+		case "trylock": // send trylock fail message
+			s.broadcast("trylock", lock.uuid)
+		case "lock":
+			s.locks[lock.key] = append(locks, lock)
+		}
 	}
 }
 func (s *ZBus) _unlock(l Lock) {
diff --git a/internal/zbus/zdb.go b/internal/zbus/zdb.go
index 55f61fc..79f327b 100644
--- a/internal/zbus/zdb.go
+++ b/internal/zbus/zdb.go
@@ -161,6 +161,7 @@ func (s *ZBus) loadLock() {
 		}
 
 		s._lock(&Lock{
+			cmd:      "lock",
 			key:      split[0],
 			uuid:     split[1],
 			duration: duration,