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 9045ad86..49734b7e 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/Spider.java
@@ -586,6 +586,7 @@ public class Spider implements Runnable, Task {
         if (threadNum <= 0) {
             throw new IllegalArgumentException("threadNum should be more than one!");
         }
+        this.executorService = executorService;
         return this;
     }