中文摘要：

通过PowerBuilder提供的列表框控件、函数的递归算法和windows提供的API函数实现了指定文件夹的智能化双向同步功能．用户只要设置同步的源文件夹和目标文件夹，系统可以自动将最新更新的文件或新增加的文件同步到对方的文件夹中．系统操作简单实用，为计算机用户的文件保存和备份提供了有力的技术支持．

英文摘要：

This paper realizes smart bidirectional file synchronization by using PowerBuilder＇s listbox control, recursive algorithm and API functions. After the user filling a source folder and a target folder, the system can automatically synchronize between the two folders with all newly modified or newly added files. This software system can be operated simply, and it can provide some technological support to help computer users save and backup files.