diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 48eb61c75d8..391005caa10 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -970,6 +970,9 @@ Release 2.7.0 - UNRELEASED
     HDFS-7798. Checkpointing failure caused by shared KerberosAuthenticator.
     (Chengbing Liu via yliu)
 
+    HDFS-6662. WebHDFS cannot open a file if its path contains "%".
+    (Gerson Carlos via wheat9)
+
     BREAKDOWN OF HDFS-7584 SUBTASKS AND RELATED JIRAS
 
       HDFS-7720. Quota by Storage Type API, tools and ClientNameNode
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/web/webhdfs/ParameterParser.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/web/webhdfs/ParameterParser.java
index e1930b057c4..57495046899 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/web/webhdfs/ParameterParser.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/web/webhdfs/ParameterParser.java
@@ -50,7 +50,7 @@ class ParameterParser {
   private final Map<String, List<String>> params;
 
   ParameterParser(QueryStringDecoder decoder, Configuration conf) {
-    this.path = decoder.path().substring(WEBHDFS_PREFIX_LENGTH);
+    this.path = QueryStringDecoder.decodeComponent(decoder.path().substring(WEBHDFS_PREFIX_LENGTH));
     this.params = decoder.parameters();
     this.conf = conf;
   }
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/hdfs/explorer.js b/hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/hdfs/explorer.js
index ca73506a619..87d47fad9e6 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/hdfs/explorer.js
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/hdfs/explorer.js
@@ -102,6 +102,13 @@
       menus.change();
     }
 
+    function encode_path(abs_path) {
+      abs_path = encodeURIComponent(abs_path);
+      var re = /%2F/g;
+      return abs_path.replace(re, '/');
+    }
+
+    abs_path = encode_path(abs_path);
     var url = '/webhdfs/v1' + abs_path + '?op=GET_BLOCK_LOCATIONS';
     $.get(url).done(function(data) {
       var d = get_response(data, "LocatedBlocks");
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/web/webhdfs/TestParameterParser.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/web/webhdfs/TestParameterParser.java
index 8b4235b8862..6a6c5d05d9b 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/web/webhdfs/TestParameterParser.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/web/webhdfs/TestParameterParser.java
@@ -52,4 +52,17 @@ public class TestParameterParser {
     final Token<DelegationTokenIdentifier> tok2 = testParser.delegationToken();
     Assert.assertTrue(HAUtil.isTokenForLogicalUri(tok2));
   }
+
+  @Test
+  public void testDecodePath() {
+    final String SCAPED_PATH = "hdfs-6662/test%25251%26%3Dtest?op=OPEN";
+    final String EXPECTED_PATH = "/hdfs-6662/test%251&=test";
+
+    Configuration conf = DFSTestUtil.newHAConfiguration(LOGICAL_NAME);
+    QueryStringDecoder decoder = new QueryStringDecoder(
+      WebHdfsHandler.WEBHDFS_PREFIX + "/"
+      + SCAPED_PATH);
+    ParameterParser testParser = new ParameterParser(decoder, conf);
+    Assert.assertEquals(EXPECTED_PATH, testParser.path());
+  }
 }