diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/schedular/Scheduler.java b/webmagic-core/src/main/java/us/codecraft/webmagic/schedular/Scheduler.java
index bf440baf..8d9649be 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/schedular/Scheduler.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/schedular/Scheduler.java
@@ -22,7 +22,7 @@ public interface Scheduler {
     /**
      * 返回下一个要抓取的链接
      * @param task 定义的任务，以满足单Scheduler多Task的情况
-     * @return
+     * @return 下一个要抓取的链接
      */
     public Request poll(Task task);
 
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/Html.java b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/Html.java
index 099f5074..114eef99 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/Html.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/Html.java
@@ -4,6 +4,7 @@ import java.util.ArrayList;
 import java.util.List;
 
 /**
+ * 可抽取的html文本。<br>
  * @author code4crafter@gmail.com <br>
  *         Date: 13-4-21
  *         Time: 上午7:54
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/PlainText.java b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/PlainText.java
index 0137de81..9e8d1941 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/PlainText.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/PlainText.java
@@ -6,6 +6,7 @@ import java.util.ArrayList;
 import java.util.List;
 
 /**
+ * 可抽取的纯文本，不包括xpath和css selector实现。<br>
  * @author code4crafter@gmail.com <br>
  * Date: 13-4-21
  * Time: 上午7:54
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/RegexSelector.java b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/RegexSelector.java
index 49fbffd0..e95138b7 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/RegexSelector.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/RegexSelector.java
@@ -9,6 +9,7 @@ import java.util.regex.Pattern;
 import java.util.regex.PatternSyntaxException;
 
 /**
+ * 正则表达式抽取器。<br>
  * @author code4crafter@gmail.com <br>
  * Date: 13-4-21
  * Time: 上午7:09
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/ReplaceSelector.java b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/ReplaceSelector.java
index 1ce7c4d5..38b95f78 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/ReplaceSelector.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/ReplaceSelector.java
@@ -6,6 +6,7 @@ import java.util.regex.Pattern;
 import java.util.regex.PatternSyntaxException;
 
 /**
+ * 对文本进行替换。<br>
  * @author code4crafter@gmail.com <br>
  * Date: 13-4-21
  * Time: 上午7:09
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/Selectable.java b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/Selectable.java
index 932115cd..1b0ba10a 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/Selectable.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/Selectable.java
@@ -3,6 +3,7 @@ package us.codecraft.webmagic.selector;
 import java.util.List;
 
 /**
+ * 可进行抽取的文本。<br>
  * @author code4crafter@gmail.com <br>
  * Date: 13-4-20
  * Time: 下午7:51
@@ -20,8 +21,8 @@ public interface Selectable {
     /**
      * select list with css selector
      *
-     * @param
-     * @return
+     * @param selector css selector expression
+     * @return new Selectable after extract
      */
     public Selectable $(String selector);
 
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/Selector.java b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/Selector.java
index f7771cfb..845c0b6c 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/Selector.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/Selector.java
@@ -3,6 +3,7 @@ package us.codecraft.webmagic.selector;
 import java.util.List;
 
 /**
+ * 抽取器。<br>
  * @author code4crafter@gmail.com <br>
  * Date: 13-4-20
  * Time: 下午8:02
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/SelectorFactory.java b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/SelectorFactory.java
index 2fa78d32..1dd56e01 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/selector/SelectorFactory.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/selector/SelectorFactory.java
@@ -7,6 +7,7 @@ import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 
 /**
+ * 产生selector的工厂。<br>
  * @author code4crafter@gmail.com <br>
  * Date: 13-4-21
  * Time: 上午7:56
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/utils/ThreadUtils.java b/webmagic-core/src/main/java/us/codecraft/webmagic/utils/ThreadUtils.java
index ebe61198..d6876c71 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/utils/ThreadUtils.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/utils/ThreadUtils.java
@@ -6,6 +6,7 @@ import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 
 /**
+ * 线程工具类。<br>
  * @author code4crafer@gmail.com
  *         Date: 13-6-23
  *         Time: 下午7:11
diff --git a/webmagic-core/src/main/java/us/codecraft/webmagic/utils/UrlUtils.java b/webmagic-core/src/main/java/us/codecraft/webmagic/utils/UrlUtils.java
index 0b7201d6..9f038bc8 100644
--- a/webmagic-core/src/main/java/us/codecraft/webmagic/utils/UrlUtils.java
+++ b/webmagic-core/src/main/java/us/codecraft/webmagic/utils/UrlUtils.java
@@ -6,6 +6,7 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 /**
+ * url及html处理工具类。<br>
  * @author code4crafter@gmail.com <br>
  * Date: 13-4-21
  * Time: 下午1:52
@@ -18,7 +19,7 @@ public class UrlUtils {
      * 将url想对地址转化为绝对地址
      * @param url url地址
      * @param refer url地址来自哪个页面
-     * @return
+     * @return url绝对地址
      */
     public static String canonicalizeUrl(String url, String refer) {
         if (StringUtils.isBlank(url) || StringUtils.isBlank(refer)) {