The core problem of the single sign-on (SSO) is a identity authentication problem between different systems. Early single sign-on system way of solving this problem is to use static password login, Static password uses trival and security is not high. The article on enterprise portal puts forward the design scheme of the dynamic password authentication in the unified information platform among each system, This paper presents the design schemes of client for the single sign on system, achieves the unified login problem of different accounts and password of the different systems, and realizes the coordination and unification of the system in dynamic session management mechanism.