Abstract: With the rapid development of network technology, the diversification phenomenon of information acquisition means has become increasingly evident. Library is no longer the traditional information center, and the contradiction between supply and demand has become one of the main contradiction in current development of library. How to promote the further enhancement on the quality and efficiency of library information service system, and get rid of the existing difficulties to continue the healthy development through supply-side reform, is the core problem for library workers. This paper took the supply-side reform as the breakthrough point to study the changes about the idea of library information service system, and analyzed its structure as well as the transformation and upgrading operation mode.