diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/HttpClientDownloader.java b/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/HttpClientDownloader.java
index b6f0034..1bee564 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/HttpClientDownloader.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/HttpClientDownloader.java
@@ -34,6 +34,8 @@ public class HttpClientDownloader implements Downloader {
 
     private Logger logger = Logger.getLogger(getClass());
 
+    private HttpClientPool httpClientPool;
+
     private int poolSize = 1;
 
     /**
@@ -58,6 +60,13 @@ public class HttpClientDownloader implements Downloader {
         return (Html) page.getHtml();
     }
 
+    private HttpClientPool getHttpClientPool(){
+        if (httpClientPool==null){
+            httpClientPool = new HttpClientPool(poolSize);
+        }
+        return httpClientPool;
+    }
+
     @Override
     public Page download(Request request, Task task) {
         Site site = null;
@@ -78,7 +87,7 @@ public class HttpClientDownloader implements Downloader {
             acceptStatCode.add(200);
         }
         logger.info("downloading page " + request.getUrl());
-        HttpClient httpClient = HttpClientPool.getInstance(poolSize).getClient(site);
+        HttpClient httpClient = getHttpClientPool().getClient(site);
         try {
             HttpGet httpGet = new HttpGet(request.getUrl());
             if (headers!=null){
@@ -150,6 +159,7 @@ public class HttpClientDownloader implements Downloader {
     @Override
     public void setThread(int thread) {
         poolSize = thread;
+        httpClientPool = new HttpClientPool(thread);
     }
 
     private void handleGzip(HttpResponse httpResponse) {
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/HttpClientPool.java b/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/HttpClientPool.java
index f3b72b6..c882836 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/HttpClientPool.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/downloader/HttpClientPool.java
@@ -24,23 +24,19 @@ import java.util.Map;
  */
 public class HttpClientPool {
 
-    public static volatile HttpClientPool INSTANCE;
-
-    public static HttpClientPool getInstance(int poolSize) {
-        if (INSTANCE == null) {
-            synchronized (HttpClientPool.class) {
-                if (INSTANCE == null) {
-                    INSTANCE = new HttpClientPool(poolSize);
-                }
-            }
-        }
-        return INSTANCE;
-    }
-
     private int poolSize;
 
-    private HttpClientPool(int poolSize) {
+    private PoolingClientConnectionManager connectionManager;
+
+    public HttpClientPool(int poolSize) {
         this.poolSize = poolSize;
+        SchemeRegistry schemeRegistry = new SchemeRegistry();
+        schemeRegistry.register(new Scheme("http", 80, PlainSocketFactory.getSocketFactory()));
+        schemeRegistry.register(new Scheme("https", 443, SSLSocketFactory.getSocketFactory()));
+
+        connectionManager = new PoolingClientConnectionManager(schemeRegistry);
+        connectionManager.setMaxTotal(poolSize);
+        connectionManager.setDefaultMaxPerRoute(100);
     }
 
     public HttpClient getClient(Site site) {
@@ -58,7 +54,6 @@ public class HttpClientPool {
             params.setIntParameter(CoreConnectionPNames.CONNECTION_TIMEOUT, 3000);
         }
 
-
         params.setParameter(ClientPNames.COOKIE_POLICY, CookiePolicy.BEST_MATCH);
         HttpProtocolParamBean paramsBean = new HttpProtocolParamBean(params);
         paramsBean.setVersion(HttpVersion.HTTP_1_1);
@@ -67,13 +62,6 @@ public class HttpClientPool {
         }
         paramsBean.setUseExpectContinue(false);
 
-        SchemeRegistry schemeRegistry = new SchemeRegistry();
-        schemeRegistry.register(new Scheme("http", 80, PlainSocketFactory.getSocketFactory()));
-        schemeRegistry.register(new Scheme("https", 443, SSLSocketFactory.getSocketFactory()));
-
-        PoolingClientConnectionManager connectionManager = new PoolingClientConnectionManager(schemeRegistry);
-        connectionManager.setMaxTotal(poolSize);
-        connectionManager.setDefaultMaxPerRoute(100);
         DefaultHttpClient httpClient = new DefaultHttpClient(connectionManager, params);
         if (site != null) {
             generateCookie(httpClient, site);
diff --git a/webmagic-samples/pom.xml b/webmagic-samples/pom.xml
index bf97b75..79238b0 100644
--- a/webmagic-samples/pom.xml
+++ b/webmagic-samples/pom.xml
@@ -5,7 +5,7 @@
     <parent>
         <artifactId>webmagic-parent</artifactId>
         <groupId>us.codecraft</groupId>
-        <version>0.3.2</version>
+        <version>0.3.3-SNAPSHOT</version>
     </parent>
     <modelVersion>4.0.0</modelVersion>