diff --git a/serial/build.gradle b/serial/build.gradle
index becdf40..46b7f05 100644
--- a/serial/build.gradle
+++ b/serial/build.gradle
@@ -8,8 +8,8 @@ android {
     defaultConfig {
         minSdkVersion 15
         targetSdkVersion 28
-        versionCode 9
-        versionName "1.2.5"
+        versionCode 10
+        versionName "1.2.6"
 
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         consumerProguardFiles 'consumer-rules.pro'
diff --git a/serial/src/main/java/org/sheedon/serial/serialport/SafeThread.java b/serial/src/main/java/org/sheedon/serial/serialport/SafeThread.java
index 0431c89..732f9e0 100644
--- a/serial/src/main/java/org/sheedon/serial/serialport/SafeThread.java
+++ b/serial/src/main/java/org/sheedon/serial/serialport/SafeThread.java
@@ -77,6 +77,24 @@ protected void execute() {
         }
     };
 
+    public void close() {
+        if (pingTimer != null) {
+            pingTimer.cancel();
+            pingTimer = null;
+        }
+
+        if (pingTask != null) {
+            pingTask.cancel();
+            pingTask = null;
+        }
+
+        if (thread != null) {
+            thread.interrupt();
+            thread = null;
+        }
+
+    }
+
     interface OnThreadHandleListener {
         void readThread();
     }
diff --git a/serial/src/main/java/org/sheedon/serial/serialport/SerialPort.java b/serial/src/main/java/org/sheedon/serial/serialport/SerialPort.java
index dcbff91..42cec38 100644
--- a/serial/src/main/java/org/sheedon/serial/serialport/SerialPort.java
+++ b/serial/src/main/java/org/sheedon/serial/serialport/SerialPort.java
@@ -19,7 +19,7 @@
  * @Email: sheedonsun@163.com
  * @Date: 2020/2/21 9:27
  */
-public class SerialPort implements SafeThread.OnThreadHandleListener{
+public class SerialPort implements SafeThread.OnThreadHandleListener {
 
     private android.serialport.SerialPort serialPort;
     private InputStream inputStream;
@@ -58,7 +58,7 @@ public SerialPort(String path, int baudRate, int flags, int interval,
         outputStream = serialPort.getOutputStream();
 
         safeThread = new SafeThread();
-        safeThread.initConfig(interval,this);
+        safeThread.initConfig(interval, this);
 
     }
 
@@ -113,7 +113,8 @@ private void dealWithData() {
      * @throws NullPointerException 如果inputStream为空，就抛出异常
      */
     private synchronized byte[] getDataByte() throws NullPointerException {
-        if (inputStream == null) throw new NullPointerException("is null");
+        if (inputStream == null)
+            return null;
         try {
             int size = inputStream.available();
             if (size > 0) {
@@ -140,7 +141,8 @@ public boolean sendMessage(String data) {
      * @param bytes 显示的16进制的字符串
      */
     private boolean setData(byte[] bytes) throws NullPointerException {
-        if (outputStream == null) throw new NullPointerException("outputStream为空");
+        if (outputStream == null)
+            return false;
         try {
             outputStream.write(bytes);
             return true;//发送成功
@@ -154,6 +156,10 @@ private boolean setData(byte[] bytes) throws NullPointerException {
      * 关闭串口
      */
     public void closeSerialPort() {
+        if(safeThread != null){
+            safeThread.close();
+            safeThread = null;
+        }
         if (serialPort != null) {
             serialPort.close();
             serialPort = null;