(This paper analyzes the problems and difficulties in the use and promotion of the knowledge management system. Through in-depth research on the combination of knowledge management and SaaS mode, it proposes to build a library cloud computing public knowledge service platform, improve the efficiency and effect of knowledge services by using the characteristics of cloud computing technology, and provide users with diversified, personalized, accurate and professional knowledge services, It also discusses the use mode of knowledge management system based on SaaS mode.)