diff --git a/Aria/src/main/java/com/arialyy/aria/core/queue/DownloadTaskQueue.java b/Aria/src/main/java/com/arialyy/aria/core/queue/DownloadTaskQueue.java
index 9e6fde29..59bd9de3 100644
--- a/Aria/src/main/java/com/arialyy/aria/core/queue/DownloadTaskQueue.java
+++ b/Aria/src/main/java/com/arialyy/aria/core/queue/DownloadTaskQueue.java
@@ -25,6 +25,7 @@ import com.arialyy.aria.core.scheduler.DownloadSchedulers;
 import com.arialyy.aria.core.scheduler.IDownloadSchedulers;
 import com.arialyy.aria.core.task.Task;
 import com.arialyy.aria.core.task.TaskFactory;
+import com.arialyy.aria.util.Configuration;
 
 /**
  * Created by lyy on 2016/8/17.
@@ -106,7 +107,7 @@ public class DownloadTaskQueue implements ITaskQueue {
   }
 
   @Override public void reTryStart(Task task) {
-    if (task == null){
+    if (task == null) {
       Log.w(TAG, "重试下载失败，task 为null");
       return;
     }
@@ -126,7 +127,32 @@ public class DownloadTaskQueue implements ITaskQueue {
   }
 
   @Override public void setDownloadNum(int downloadNum) {
+    //原始长度
+    int size = Configuration.getInstance().getDownloadNum();
+    int diff = downloadNum - size;
+    if (size == downloadNum){
+      Log.d(TAG, "设置的下载任务数和配置文件的下载任务数一直，跳过");
+      return;
+    }
+    //设置的任务数小于配置任务数
+    if (diff <= -1 && mExecutePool.size() >= size) {
+      for (int i = 0, len = Math.abs(diff); i < len; i++) {
+        Task eTask = mExecutePool.pollTask();
+        if (eTask != null) {
+          stopTask(eTask);
+        }
+      }
+    }
     mExecutePool.setDownloadNum(downloadNum);
+    if (diff >= 1) {
+      for (int i = 0; i < diff; i++) {
+        Task nextTask = getNextTask();
+        if (nextTask != null
+            && nextTask.getDownloadEntity().getState() == DownloadEntity.STATE_WAIT) {
+          startTask(nextTask);
+        }
+      }
+    }
   }
 
   @Override public Task createTask(Object target, DownloadEntity entity) {
diff --git a/Aria/src/main/java/com/arialyy/aria/core/queue/pool/CachePool.java b/Aria/src/main/java/com/arialyy/aria/core/queue/pool/CachePool.java
index f2adb5e2..8f710491 100644
--- a/Aria/src/main/java/com/arialyy/aria/core/queue/pool/CachePool.java
+++ b/Aria/src/main/java/com/arialyy/aria/core/queue/pool/CachePool.java
@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-
 package com.arialyy.aria.core.queue.pool;
 
 import android.text.TextUtils;
@@ -25,6 +24,7 @@ import com.arialyy.aria.core.task.Task;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.TimeUnit;
 
 /**
  * Created by lyy on 2016/8/14.
@@ -35,6 +35,7 @@ public class CachePool implements IPool {
   private static final    Object    LOCK     = new Object();
   private static final    int       MAX_NUM  = Integer.MAX_VALUE;  //最大下载任务数
   private static volatile CachePool INSTANCE = null;
+  private static final    long      TIME_OUT = 1000;
   private Map<String, Task>         mCacheArray;
   private LinkedBlockingQueue<Task> mCacheQueue;
 
@@ -75,13 +76,19 @@ public class CachePool implements IPool {
 
   @Override public Task pollTask() {
     synchronized (LOCK) {
-      Task task = mCacheQueue.poll();
-      if (task != null) {
-        String url = task.getDownloadEntity().getDownloadUrl();
-        mCacheArray.remove(CommonUtil.keyToHashKey(url));
+      try {
+        Task task = null;
+        task = mCacheQueue.poll(TIME_OUT, TimeUnit.MICROSECONDS);
+        if (task != null) {
+          String url = task.getDownloadEntity().getDownloadUrl();
+          mCacheArray.remove(CommonUtil.keyToHashKey(url));
+        }
+        return task;
+      } catch (InterruptedException e) {
+        e.printStackTrace();
       }
-      return task;
     }
+    return null;
   }
 
   @Override public Task getTask(String downloadUrl) {
diff --git a/Aria/src/main/java/com/arialyy/aria/core/queue/pool/ExecutePool.java b/Aria/src/main/java/com/arialyy/aria/core/queue/pool/ExecutePool.java
index 6f3f5009..a3a1c911 100644
--- a/Aria/src/main/java/com/arialyy/aria/core/queue/pool/ExecutePool.java
+++ b/Aria/src/main/java/com/arialyy/aria/core/queue/pool/ExecutePool.java
@@ -137,12 +137,18 @@ public class ExecutePool implements IPool {
 
   @Override public Task pollTask() {
     synchronized (LOCK) {
-      Task task = mExecuteQueue.poll();
-      if (task != null) {
-        String url = task.getDownloadEntity().getDownloadUrl();
-        mExecuteArray.remove(CommonUtil.keyToHashKey(url));
+      try {
+        Task task = null;
+        task = mExecuteQueue.poll(TIME_OUT, TimeUnit.MICROSECONDS);
+        if (task != null) {
+          String url = task.getDownloadEntity().getDownloadUrl();
+          mExecuteArray.remove(CommonUtil.keyToHashKey(url));
+        }
+        return task;
+      } catch (InterruptedException e) {
+        e.printStackTrace();
       }
-      return task;
+      return null;
     }
   }