diff --git a/interface/ri_install.py b/interface/ri_install.py
index f74db83..7691f96 100644
--- a/interface/ri_install.py
+++ b/interface/ri_install.py
@@ -21,6 +21,7 @@ import getopt
 import ri_oper
 import os
 import os.path
+import ri_data
 def install_over(ret):
 	if ri_oper.Rate.value == 100 and ret == 0:
 		if display.set_task_over():
diff --git a/interface/ri_tk_cmd.py b/interface/ri_tk_cmd.py
index 447ca3e..700b12d 100644
--- a/interface/ri_tk_cmd.py
+++ b/interface/ri_tk_cmd.py
@@ -61,9 +61,18 @@ def mp_top_init():
             if fs == fs_values[i]:
                 ri_widget.Widget.dict['mp_top_fs'].tk_widget.selection_set(i)
 
+def mp_top_check(dev,dir):
+    '''check mount point'''
+    if dir:
+        for d in ri_data.MountPoint.dict.values(): 
+            if d.device == dev :continue
+            if d.directory == dir : return True
+    return False
+
 def mp_top_ok():
     ''' mount dir top window OK '''
     l = []
+    the_same = False
     for itm in eval(display.var_dict['mount.list'].get()):
         dev = itm.split()[0]
         dev2 = display.var_dict['mp_top_dev'].get()
@@ -81,6 +90,9 @@ def mp_top_ok():
                 fs = ri_data.Partition.dict[dev].filesystem
             else:
                 fs = ' '
+            if mp_top_check(dev,dr):
+                the_same = True
+                dr = ri_data.MountPoint.dict[dev].directory
             s2 = dev.ljust(10) + dr.ljust(10) + fs.ljust(10) + fm.ljust(4) + sz.ljust(6) + ri_data.Partition.unit
             l.append(s2)
             # make change in internal data structure
@@ -90,6 +102,8 @@ def mp_top_ok():
 
     display.var_dict['mount.list'].set(value=tuple(l))
     ri_widget.TopWindow.dict['mount_list_modify'].hide()
+    if the_same:
+        ri_widget.MessageBox.dict['check_mount_point'].show()
 
 def mp_top_cancel():
     ''' mount dir top window cancel '''
diff --git a/xml/interface.xml b/xml/interface.xml
index d281f62..f6f206a 100644
--- a/xml/interface.xml
+++ b/xml/interface.xml
@@ -728,6 +728,7 @@ row 4 |                                                            |
   <message_box name='raid_delete_warning' type='showwarning' title='raid deleting' message='#raid-delete-warning'/>
   <message_box name='raid_add_active_numbers' type='showwarning' title='number' message='#raid-add-active-numbers'/>
   <message_box name='raid_add_active_numbers_2' type='showwarning' title='number' message='#raid-add-active-numbers-2'/>
+  <message_box name='check_mount_point' type='showwarning' title='checking' message='#check-mount-point'/>
 <!--
                 column 0              column 1
           ________________________________________________
@@ -856,6 +857,11 @@ row 4 |                                                            |
     </widget>
   </widget>
 
+    <text key='#check-mount-point'>
+        <English>The mount point has been used</English>
+        <Chinese>挂载点已经被使用</Chinese>
+    </text>   
+	
 	<text key='#dependency.help'>
     <English>
     There are two kinds of dependent relationships. Dependent Functions and Dependent Packages.