In the information age, IT companies pay more and more attention to the quality of service. Social network service providers concentrates on saving the cost and developing products with better quality. The explosion of Web service has provided good opportunities for these companies, and also brought severe challenges to them. Therefore, the efficiency and the reusability would be the important factors that developers should consider about. In order to meet the requirements above, this paper designs the model of social network service with Service-Oriented Architecture Modeling Language (SOAML), which supports the service-oriented modeling and design.