diff --git a/hadoop-yarn-project/CHANGES.txt b/hadoop-yarn-project/CHANGES.txt
index e71da2d182..c028043b37 100644
--- a/hadoop-yarn-project/CHANGES.txt
+++ b/hadoop-yarn-project/CHANGES.txt
@@ -310,6 +310,8 @@ Release 2.7.0 - UNRELEASED
     YARN-2799. Cleanup TestLogAggregationService based on the change in YARN-90.
     (Zhihai Xu via junping_du)
 
+    YARN-3230. Clarify application states on the web UI. (Jian He via wangda)
+
   OPTIMIZATIONS
 
     YARN-2990. FairScheduler's delay-scheduling always waits for node-local and 
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppBlock.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppBlock.java
index 1856d7526e..c2b376e830 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppBlock.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppBlock.java
@@ -32,8 +32,10 @@
 import org.apache.hadoop.util.StringUtils;
 import org.apache.hadoop.yarn.api.records.ApplicationAccessType;
 import org.apache.hadoop.yarn.api.records.ApplicationId;
+import org.apache.hadoop.yarn.api.records.FinalApplicationStatus;
 import org.apache.hadoop.yarn.api.records.QueueACL;
 import org.apache.hadoop.yarn.api.records.Resource;
+import org.apache.hadoop.yarn.api.records.YarnApplicationState;
 import org.apache.hadoop.yarn.server.resourcemanager.RMContext;
 import org.apache.hadoop.yarn.server.resourcemanager.ResourceManager;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMApp;
@@ -131,8 +133,9 @@ protected void render(Block html) {
         ._("Name:", app.getName())
         ._("Application Type:", app.getApplicationType())
         ._("Application Tags:", app.getApplicationTags())
-        ._("State:", app.getState())
-        ._("FinalStatus:", app.getFinalStatus())
+        ._("YarnApplicationState:", clarifyAppState(app.getState()))
+        ._("FinalStatus reported by AM:",
+          clairfyAppFinalStatus(app.getFinalStatus()))
         ._("Started:", Times.format(app.getStartTime()))
         ._("Elapsed:",
             StringUtils.formatTime(Times.elapsed(app.getStartTime(),
@@ -198,4 +201,30 @@ protected void render(Block html) {
     table._();
     div._();
   }
+
+  private String clarifyAppState(YarnApplicationState state) {
+    String ret = state.toString();
+    switch (state) {
+    case NEW:
+      return ret + ": waiting for application to be initialized";
+    case NEW_SAVING:
+      return ret + ": waiting for application to be persisted in state-store.";
+    case SUBMITTED:
+      return ret + ": waiting for application to be accepted by scheduler.";
+    case ACCEPTED:
+      return ret + ": waiting for AM container to be allocated, launched and"
+          + " register with RM.";
+    case RUNNING:
+      return ret + ": AM has registered with RM and started running.";
+    default:
+      return ret;
+    }
+  }
+
+  private String clairfyAppFinalStatus(FinalApplicationStatus status) {
+    if (status == FinalApplicationStatus.UNDEFINED) {
+      return "Application has not completed yet.";
+    }
+    return status.toString();
+  }
 }
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppsBlock.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppsBlock.java
index 096a2b6a7d..054a1a7020 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppsBlock.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/AppsBlock.java
@@ -30,6 +30,7 @@
 import org.apache.commons.lang.StringEscapeUtils;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.yarn.api.records.ApplicationId;
+import org.apache.hadoop.yarn.api.records.FinalApplicationStatus;
 import org.apache.hadoop.yarn.api.records.YarnApplicationState;
 import org.apache.hadoop.yarn.server.resourcemanager.ResourceManager;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMApp;
@@ -65,7 +66,7 @@ class AppsBlock extends HtmlBlock {
             th(".queue", "Queue").
             th(".starttime", "StartTime").
             th(".finishtime", "FinishTime").
-            th(".state", "State").
+            th(".state", "YarnApplicationState").
             th(".finalstatus", "FinalStatus").
             th(".progress", "Progress").
             th(".ui", "Tracking UI")._()._().
@@ -101,7 +102,8 @@ class AppsBlock extends HtmlBlock {
       .append(appInfo.getStartTime()).append("\",\"")
       .append(appInfo.getFinishTime()).append("\",\"")
       .append(appInfo.getState()).append("\",\"")
-      .append(appInfo.getFinalStatus()).append("\",\"")
+      .append(appInfo.getFinalStatus() == FinalApplicationStatus.UNDEFINED ?
+          "N/A" : appInfo.getFinalStatus()).append("\",\"")
       // Progress bar
       .append("<br title='").append(percent)
       .append("'> <div class='").append(C_PROGRESSBAR).append("' title='")
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/dao/AppInfo.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/dao/AppInfo.java
index 2b0dedc51c..66940cbea4 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/dao/AppInfo.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/dao/AppInfo.java
@@ -200,8 +200,8 @@ public String getName() {
     return this.name;
   }
 
-  public String getState() {
-    return this.state.toString();
+  public YarnApplicationState getState() {
+    return this.state;
   }
 
   public float getProgress() {
@@ -216,8 +216,8 @@ public String getNote() {
     return this.diagnostics;
   }
 
-  public String getFinalStatus() {
-    return this.finalStatus.toString();
+  public FinalApplicationStatus getFinalStatus() {
+    return this.finalStatus;
   }
 
   public String getTrackingUrl() {