其实只需要改一个文件即可。
phpcms\model\content_model.class.php下的

    private function update_category_items($catid,$action = 'add',$cache = 0)

{
                    $this->category_db = pc_base::load_model

('category_model');
                    if($action=='add') {
                            $this->category_db->update(array

('items'=>'+=1'),array('catid'=>$catid));
                    }  else {
                            //$this->category_db->update(array('items'=>'-

=1'),array('catid'=>$catid));
                    }
                    if($cache) $this->cache_items();
            }

只要注释下面的句就可以了