Cloud environment construction is to manage the resource and service of different business systems in a unified way,to provide a unified interface for users. To ensure the safety of resources and services in cloud environment, and for the convenience of users to use these resources and services, the design for a single sign-on model is necessary. It can avoid repeated verification. On the basis of the analysis of the demand for cloud computing single sign-on, this paper designs the overall structure and process of the system.