diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java b/webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java
index 11a671f7..a35af70a 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java
@@ -85,7 +85,7 @@ public class Spider implements Runnable, Task {
 
     protected AtomicInteger stat = new AtomicInteger(STAT_INIT);
 
-    protected boolean exitWhenComplete = true;
+    protected volatile boolean exitWhenComplete = true;
 
     protected final static int STAT_INIT = 0;
 
@@ -598,6 +598,13 @@ public class Spider implements Runnable, Task {
         }
     }
 
+    /**
+     * Stop when all tasks in the queue are completed and all worker threads are also completed
+     */
+    public void stopWhenComplete(){
+        this.exitWhenComplete = true;
+    }
+
     /**
      * start with more than one threads
      *