The singleton pattern is a design pattern used for Web development,the class instantiate the only object inside the class applied the singleton pattern, and provide the object to the whole application through the static methods of the class, play a shared global role. Application of this kind of mode can reduce the application's resource consumption and improve operational efficiency. But it is difficult when competency system task or an instance exists only. Multiple instances model is as an extension of singleton pattern. It can avoid disorderly generating the class body object through generating a finite object instance.It is a very good solution to finish the task unfinished by the only object also. This model can be said to be continuation and expansion of the singleton pattern.