diff --git a/CHANGES.txt b/CHANGES.txt
index a753acecf0..1373650452 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -173,6 +173,9 @@ Trunk (unreleased changes)
     HADOOP-7302. webinterface.private.actions should be renamed and moved to
     the MapReduce project. (Ari Rabkin via todd)
 
+    HADOOP-7329. Improve help message for "df" to include "-h" flag.
+    (Xie Xianshan via todd)
+
   OPTIMIZATIONS
 
   BUG FIXES
diff --git a/src/java/org/apache/hadoop/fs/shell/FsUsage.java b/src/java/org/apache/hadoop/fs/shell/FsUsage.java
index 70d781bc64..cf95f6a98a 100644
--- a/src/java/org/apache/hadoop/fs/shell/FsUsage.java
+++ b/src/java/org/apache/hadoop/fs/shell/FsUsage.java
@@ -55,12 +55,14 @@ protected String formatSize(long size) {
   /** Show the size of a partition in the filesystem */
   public static class Df extends FsUsage {
     public static final String NAME = "df";
-    public static final String USAGE = "[<path> ...]";
+    public static final String USAGE = "[-h] [<path> ...]";
     public static final String DESCRIPTION =
       "Shows the capacity, free and used space of the filesystem.\n"+
       "If the filesystem has multiple partitions, and no path to a\n" +
       "particular partition is specified, then the status of the root\n" +
-      "partitions will be shown.";
+      "partitions will be shown.\n" +
+      "  -h   Formats the sizes of files in a human-readable fashion\n" +
+      "       rather than a number of bytes.\n\n";
     
     @Override
     protected void processOptions(LinkedList<String> args)