diff --git a/src/main/java/com/taobao/gecko/core/nio/impl/SelectorManager.java b/src/main/java/com/taobao/gecko/core/nio/impl/SelectorManager.java
index 706ebf9..aa430c3 100644
--- a/src/main/java/com/taobao/gecko/core/nio/impl/SelectorManager.java
+++ b/src/main/java/com/taobao/gecko/core/nio/impl/SelectorManager.java
@@ -18,10 +18,10 @@
 import java.io.IOException;
 import java.nio.channels.SelectableChannel;
 import java.nio.channels.SelectionKey;
-
+
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-
+
 import com.taobao.gecko.core.config.Configuration;
 import com.taobao.gecko.core.core.EventType;
 import com.taobao.gecko.core.core.Session;
@@ -63,8 +63,10 @@ public SelectorManager(final int selectorPoolSize, final NioController controlle
         }
         this.dividend = this.reactorSet.length - 1;
     }
-
-    private volatile boolean started;
+
+    //SelectorManager status: new -> started -> stopped
+    private volatile boolean started = false;
+	private volatile boolean stopped = false;
 
 
     public int getSelectorCount() {
@@ -76,7 +78,8 @@ public synchronized void start() {
         if (this.started) {
             return;
         }
-        this.started = true;
+		this.started = true;
+		this.stopped = false;
         for (final Reactor reactor : this.reactorSet) {
             reactor.start();
         }
@@ -101,7 +104,8 @@ public synchronized void stop() {
         if (!this.started) {
             return;
         }
-        this.started = false;
+        this.started = false;
+        this.stopped = true;
         for (final Reactor reactor : this.reactorSet) {
             reactor.interrupt();
         }
@@ -148,7 +152,11 @@ void awaitReady() {
                 }
                 catch (final InterruptedException e) {
                     Thread.currentThread().interrupt();// reset interrupt status
-                }
+                }
+                
+				if (this.stopped) {
+					throw new IllegalStateException("SelectorManager was stopped");
+				}
             }
         }
     }