[Purpose/significance]Innovative development is the eternal theme of library career.In order to promote the modernization of domestic public library governance capacity, and achieve the transformation and transcendence of development models, we need to get rid of the path dependence. [Method/process] This paper explored the connotation and extension of the system in the development process from the perspective of institutional analysis. [Result/conclusion] The system of the library councilis the distinctive mark of the modernization of public library governance capacity. The institutional dilemma is represented in the following areas: the legal person system exists in name only, the supply of legal system is insufficient, and the bureaucracy system is deep-seated. The practical ways to the modernization of public library governance capacity in thesystem logic include the following aspects: clarifying the powers and responsibilities of the main body, collating and stipulating the governance boundary; improving the distribution of interests, reshaping the governance pattern; perfecting the monitoring mechanism, standardizing the governance behavior; promoting the information disclosure mechanism and making the governance process transparent.