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 99b71e0..60eacee 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
@@ -43,12 +43,22 @@ public class UrlUtils {
             if (url.startsWith("?"))
                 url = base.getPath() + url;
             URL abs = new URL(base, url);
-            return abs.toExternalForm();
+            return encodeIllegalCharacterInUrl(abs.toExternalForm());
         } catch (MalformedURLException e) {
             return "";
         }
     }
 
+    /**
+     *
+     * @param url
+     * @return
+     */
+    public static String encodeIllegalCharacterInUrl(String url) {
+        //TODO more charator support
+        return url.replace(" ", "%20");
+    }
+
     public static String getHost(String url) {
         String host = url;
         int i = StringUtils.ordinalIndexOf(url, "/", 3);
@@ -101,9 +111,9 @@ public class UrlUtils {
             stringBuilder.append("\"").append(canonicalizeUrl(matcher.group(2), url)).append("\"");
             lastEnd = matcher.end();
         }
-		if (!modified) {
-			return html;
-		}
+        if (!modified) {
+            return html;
+        }
         stringBuilder.append(StringUtils.substring(html, lastEnd));
         return stringBuilder.toString();
     }
diff --git a/webmagic-core/src/test/java/us/codecraft/webmagic/downloader/HttpClientDownloaderTest.java b/webmagic-core/src/test/java/us/codecraft/webmagic/downloader/HttpClientDownloaderTest.java
index ac01926..e6fe5ae 100644
--- a/webmagic-core/src/test/java/us/codecraft/webmagic/downloader/HttpClientDownloaderTest.java
+++ b/webmagic-core/src/test/java/us/codecraft/webmagic/downloader/HttpClientDownloaderTest.java
@@ -8,6 +8,8 @@ import us.codecraft.webmagic.Site;
 import us.codecraft.webmagic.Task;
 import us.codecraft.webmagic.selector.Html;
 
+import java.io.UnsupportedEncodingException;
+
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.Assert.assertTrue;
 
@@ -32,6 +34,12 @@ public class HttpClientDownloaderTest {
         assertTrue(!html.getText().isEmpty());
     }
 
+    @Test(expected = IllegalArgumentException.class)
+    public void testDownloaderInIllegalUrl() throws UnsupportedEncodingException {
+        HttpClientDownloader httpClientDownloader = new HttpClientDownloader();
+        httpClientDownloader.download("http://www.oschina.net/>");
+    }
+
     @Test
     public void testCycleTriedTimes() {
         HttpClientDownloader httpClientDownloader = new HttpClientDownloader();
diff --git a/webmagic-core/src/test/java/us/codecraft/webmagic/utils/UrlUtilsTest.java b/webmagic-core/src/test/java/us/codecraft/webmagic/utils/UrlUtilsTest.java
index 1e403c4..565fde4 100644
--- a/webmagic-core/src/test/java/us/codecraft/webmagic/utils/UrlUtilsTest.java
+++ b/webmagic-core/src/test/java/us/codecraft/webmagic/utils/UrlUtilsTest.java
@@ -38,17 +38,22 @@ public class UrlUtilsTest {
 
         originHtml = "<a href=\"/start a\">";
         replacedHtml = UrlUtils.fixAllRelativeHrefs(originHtml, "http://www.dianping.com/");
-        assertThat(replacedHtml).isEqualTo("<a href=\"http://www.dianping.com/start a\">");
+        assertThat(replacedHtml).isEqualTo("<a href=\"http://www.dianping.com/start%20a\">");
 
         originHtml = "<a href='/start a'>";
         replacedHtml = UrlUtils.fixAllRelativeHrefs(originHtml, "http://www.dianping.com/");
-        assertThat(replacedHtml).isEqualTo("<a href=\"http://www.dianping.com/start a\">");
+        assertThat(replacedHtml).isEqualTo("<a href=\"http://www.dianping.com/start%20a\">");
 
         originHtml = "<a href=/start tag>";
         replacedHtml = UrlUtils.fixAllRelativeHrefs(originHtml, "http://www.dianping.com/");
         assertThat(replacedHtml).isEqualTo("<a href=\"http://www.dianping.com/start\" tag>");
     }
 
+    @Test
+    public void test(){
+        UrlUtils.canonicalizeUrl("start tag", "http://www.dianping.com/");
+    }
+
     @Test
     public void testGetDomain(){
         String url = "http://www.dianping.com/aa/";