diff --git a/backend/SystemUpdater/UpdateManager.py b/backend/SystemUpdater/UpdateManager.py
index e08419a..c1ed157 100644
--- a/backend/SystemUpdater/UpdateManager.py
+++ b/backend/SystemUpdater/UpdateManager.py
@@ -98,32 +98,49 @@ class UpdateManager():
     def start_deb_install(self, deb_path = "", is_install = False):
         absolute_path, debname = os.path.split(deb_path)
         logging.info("About to Install Package: %s.",str(debname))
+        try:
+            (status,_error_str) = self._attempt_depends(deb_path,is_install)
+            if not status:
+                return status,_error_str
+            install_backend = get_backend(self, InstallBackend.ACTION_INSTALL_DEB)
+            install_backend.start_alone(partial_upgrade_list = deb_path, _is_install = is_install)
+        except Exception as e:
+            logging.info(str(e))
+
+    def _attempt_depends(self,deb_path,force):  # 是否查找本地依赖
         depends_list = []
         depends_pkg = []
         satisfy_list = []
         depends_count = 0
-        try:
+        _error_str = ""
+        absolute_path, debname = os.path.split(deb_path)
+        if force:
             deb = DebPackage(deb_path, self.cache)
             deb.check()
             (install, remove, unauth) = deb.required_changes
-            if len(install) > 1:
+            if remove:
+                logging.error("Need uninstall: %s.",str(remove))
+                _error_str = "Installing "+str(debname.split("_")[0])+" requires uninstalling "+str(remove)
+                return False,_error_str
+            if force == False and len(install) > 0:
+                _error_str = str(debname.split("_")[0])+" dependency is not satisfied:\n"+str(install)
+                return False,_error_str
+            # 需要查找本地依赖
+            elif len(install) > 0:
                 for pkg in self.cache:
                     if pkg.marked_install:
-                        print(pkg.name)
                         depends_pkg.append(pkg)
                     elif pkg.marked_upgrade:
-                        print(pkg.name)
                         depends_pkg.append(pkg)
             if depends_pkg: #查找本地deb包
                 depends_list = [debfile for debfile in os.listdir(absolute_path) if debfile.endswith(".deb")]
-                print(depends_list)
                 for depends in depends_pkg:
                     for debfile in depends_list:
                         if depends.name in debfile and depends.candidate.version in debfile:
                             #FIXME:检查depends包的合法性,高阶依赖
                             depends_count += 1
                             satisfy_list.append(debfile)
-                if depends_count < len(depends_pkg)-1 and is_install == False:
+                if depends_count < len(depends_pkg)-1 and force == False:
                     #本地依赖不满足
                     return False
                 else:
@@ -133,11 +150,6 @@ class UpdateManager():
                             shutil.copy(os.path.join(absolute_path,satisfy),"/var/cache/apt/archives/")
                     except Exception as e:
                         logging.info(str(e))
-            install_backend = get_backend(self, InstallBackend.ACTION_INSTALL_DEB)
-            install_backend.start_alone(partial_upgrade_list = deb_path, _is_install = is_install)
-        except Exception as e:
-            logging.info(str(e))
-
     #进行升级的操作
     def start_install(self,upgrade_mode,is_install = False,partial_upgrade_list = []):
         try:
@@ -281,7 +293,8 @@ class UpdateManager():
         """If a reboot is required to get all changes into effect."""
         return os.path.exists(os.path.join(apt_pkg.config.find_dir("Dir"),
                                         "var/run/reboot-required"))
-                                        
+
+
     def _setup_dbus(self):
         # check if there is another g-a-i already and if not setup one
         # listening on dbus
diff --git a/backend/SystemUpdater/UpdateManagerDbus.py b/backend/SystemUpdater/UpdateManagerDbus.py
index 434c3c4..fd81696 100755
--- a/backend/SystemUpdater/UpdateManagerDbus.py
+++ b/backend/SystemUpdater/UpdateManagerDbus.py
@@ -243,7 +243,9 @@ class UpdateManagerDbusController(dbus.service.Object):
             is_install = bool(_is_install)
             deb_path = str(path)
             logging.info('method InstallDebFile and is_install:%r...',is_install)
-            self.parent.start_deb_install(deb_path, is_install)
+            (status,_error_str) = self.parent.start_deb_install(deb_path, is_install)
+            if not status:
+                return True,_error_str
             return True,'success'
         except Exception as e:
             logging.error(False, str(e))
diff --git a/backend/kylin-system-updater b/backend/kylin-system-updater
index b7e0389..50bd351 100755
--- a/backend/kylin-system-updater
+++ b/backend/kylin-system-updater
@@ -66,6 +66,6 @@ if __name__ == "__main__":
   logging.info('kylin-system-updater starting ...')
 
   app = UpdateManager(options)
-  app.start_update()
+  # app.start_update()
   
   app.run()
\ No newline at end of file