diff --git a/src/com/casic/swing/ui/TimeGuardNtp.java b/src/com/casic/swing/ui/TimeGuardNtp.java
index dbce756..1b68a45 100644
--- a/src/com/casic/swing/ui/TimeGuardNtp.java
+++ b/src/com/casic/swing/ui/TimeGuardNtp.java
@@ -128,9 +128,15 @@
             @Override
             public void stateChanged(ChangeEvent e) {
                 JCheckBox checkBox = (JCheckBox) e.getSource();
-                updateTimeButton.setEnabled(!checkBox.isSelected());
-                periodComboBox.setEnabled(checkBox.isSelected());
-                startAutoSynchronize(1);
+                if (checkBox.isSelected()) {
+                    updateTimeButton.setEnabled(false);
+                    periodComboBox.setEnabled(true);
+                    startAutoSynchronize(PERIOD[0]);
+                } else {
+                    updateTimeButton.setEnabled(true);
+                    periodComboBox.setEnabled(false);
+                    stopAutoSynchronize();
+                }
             }
         });
 
@@ -170,6 +176,12 @@
         }, 0, period, TimeUnit.HOURS);
     }
 
+    private void stopAutoSynchronize() {
+        if (executorService != null) {
+            executorService.shutdown();
+        }
+    }
+
     private void updateView() {
         String result = CommandUtil.ntpDate(host);
         System.out.println("命令执行结果 ===> " + result);