diff --git a/node/etl/src/main/java/com/alibaba/otter/node/etl/select/selector/canal/OtterDownStreamHandler.java b/node/etl/src/main/java/com/alibaba/otter/node/etl/select/selector/canal/OtterDownStreamHandler.java
index 22739092..a1772c0e 100644
--- a/node/etl/src/main/java/com/alibaba/otter/node/etl/select/selector/canal/OtterDownStreamHandler.java
+++ b/node/etl/src/main/java/com/alibaba/otter/node/etl/select/selector/canal/OtterDownStreamHandler.java
@@ -24,6 +24,7 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.locks.ReentrantLock;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -61,22 +62,51 @@ public class OtterDownStreamHandler extends AbstractCanalEventDownStreamHandler<
     private int                      detectingThresoldCount   = 10;
     private int                      detectingExpCount        = 1;                                                    // 增常趋势
     private AtomicLong               detectingFailedCount     = new AtomicLong(0);                                    // 检测失败的次数
-    private AtomicLong               detectingSuccessedCount  = new AtomicLong(0);                                    // 检测成功的次数
+    private AtomicLong               detectingSuccessedCount  = new AtomicLong(0);
+    private ReentrantLock            lock                     = new ReentrantLock();                                  // 检测成功的次数
 
     public void stop() {
-        super.stop();
+        try {
+            lock.lock();
+            super.stop();
 
-        if (working.compareAndSet(true, false)) {
-            stopDetecting();
+            if (working.compareAndSet(true, false)) {
+                stopDetecting();
+            }
+        } finally {
+            lock.unlock();
         }
 
     }
 
     public List<Event> before(List<Event> events) {
+        /**
+         * 1）故障现象channel重启后，pipeline处于定位中，后台日志报超时异常。
+         * 2）故障原因：OtterDownStreamHandler里面添加打印日志发现有2个OtterDownStreamHandler.scheduler在运行
+         * 分析发现旧的scheduler没有被停止掉导致。原因是OtterDownStreamHandler.scheduler关闭后被AbstractEventParser.startHeartBeat拉起
+         */
         lastEventExecuteTime = System.currentTimeMillis();// 记录最后一条数据时间
 
-        if (working.compareAndSet(false, true)) {// 第一次有数据时
-            startDetecting();
+        if (super.isStart()) {
+            if (working.compareAndSet(false, true)) {// 第一次有数据时
+                try {
+                    // 和stop()方法竞争锁，防止stop停止调度任务，又被本方法开启调度
+                    lock.lock();
+                    if (super.isStart()) {
+                        // 再次判断是否为isStart()，因为并发的stop()随时可以使状态为停止态
+                        startDetecting();
+                    } else {
+                        // 已经被上面的并发的stop()关闭掉
+                        working.set(false);
+                    }
+                } catch (Exception e) {
+                    e.printStackTrace();
+                } finally {
+                    lock.unlock();
+                }
+
+            }
+
         }
 
         return super.before(events);