diff --git a/qinling/api/controllers/v1/function.py b/qinling/api/controllers/v1/function.py
index 18c12909..fa148ecb 100644
--- a/qinling/api/controllers/v1/function.py
+++ b/qinling/api/controllers/v1/function.py
@@ -391,6 +391,7 @@ class FunctionsController(rest.RestController):
 
                 # Package type function. 'code' and 'entry' make sense only if
                 # 'package' is provided
+                update_package = False
                 if (pre_source == constants.PACKAGE_FUNCTION and
                         values.get('package') is not None):
                     if md5sum and md5sum == pre_md5sum:
@@ -410,6 +411,7 @@ class FunctionsController(rest.RestController):
                         {"md5sum": md5sum, "source": pre_source}
                     )
                     values.pop('package')
+                    update_package = True
 
                 # Swift type function
                 if pre_source == constants.SWIFT_FUNCTION:
@@ -423,8 +425,8 @@ class FunctionsController(rest.RestController):
 
                 func_db = db_api.update_function(id, values)
 
-            # Delete function package if needed
-            if pre_md5sum:
+            # Delete the old function package if needed
+            if update_package:
                 self.storage_provider.delete(ctx.projectid, id, pre_md5sum)
 
         pecan.response.status = 200
diff --git a/qinling/tests/unit/api/controllers/v1/test_function.py b/qinling/tests/unit/api/controllers/v1/test_function.py
index 92c83950..4c682417 100644
--- a/qinling/tests/unit/api/controllers/v1/test_function.py
+++ b/qinling/tests/unit/api/controllers/v1/test_function.py
@@ -209,11 +209,11 @@ class TestFunctionController(base.APITest):
             resp.json['faultstring']
         )
 
+    @mock.patch('qinling.storage.file_system.FileSystemStorage.delete')
     @mock.patch('qinling.utils.etcd_util.delete_function')
     @mock.patch('qinling.rpc.EngineClient.delete_function')
-    def test_put_cpu_and_memorysize(
-            self, mock_delete_func, mock_etcd_del
-    ):
+    def test_put_cpu_and_memorysize(self, mock_delete_func, mock_etcd_del,
+                                    mock_storage_delete):
         # Test for updating cpu/mem with good input values.
         db_func = self.create_function(runtime_id=self.runtime_id)
 
@@ -235,6 +235,7 @@ class TestFunctionController(base.APITest):
         )
         mock_delete_func.assert_called_once_with(db_func.id)
         mock_etcd_del.assert_called_once_with(db_func.id)
+        self.assertFalse(mock_storage_delete.called)
 
     @mock.patch('qinling.utils.etcd_util.delete_function')
     @mock.patch('qinling.rpc.EngineClient.delete_function')