Abstract: Mr.Li jingyu is a citizen library scientist ignored by the library community.With the help of his works and related documents，Mr.Li jingyu sorted out his library activities and achievements from 1933 to 1937.The three-level library service system is adopted with the simple rural teachers‘library as the main library，the rural residents' library as the branch library，and the traveling books（traveling cases and library）as the mobile station.It is suggested that the division and management of the library should be based on local conditions and be bold and innovative.Pay attention to the general education of library knowledge and the cultivation of professional talents；Actively participate in industry activities，speak for the village library.His theory of public service，the concept of unit and the three-level service system can be used for reference in the construction of grassroots libraries，general branch libraries and the revitalization of rural culture.

Key words: The republic of China；Li Jing-yu；Service system；Public library