The application framework and implementing pattern of the SaaS have been analyzed to meet the demands of information technology application of cooperative marketing system for cigarette manufactories and commerce enterprises of tobacco industry of China in this paper. Under the framework and pattern of the SaaS, the MVC design pattern has been improved to satisfy the application requirement of the cooperative marketing system. With the improved MVC pattern, the Information System of Cooperative Marketing of Tobacco Industry (ISCMTI) as a common information service platform has been designed in the paper.