Abstract: With the increasing digital information application platforms, more and more universities start to adopt unified authentication. To better service the users and increase service quality, university libraries should combine library digital platforms with university's unified authentication, which need to make different development focusing on different system. This paper took the library main website and CALIS federal authentication as examples, and gave deep introduction and analysis on the CAS and CALIS flow programs, and unified the library service platforms with CAS single sign-on system, so as to reduce the maintenance requirement of every library digital platform's user login database and improve users' experience.