The program abstract the finite cover system of 3d nmm as independent data classes , and give the definition and implement of the classes , and manage these data classes by techniques of tree structure 程序将三维数值流形方法的有限覆盖系统抽象为一些独立的数据类,给出了类的描述和它们的实现方法,并用树状结构对这些数据类进行管理。