Promoting the county's general-branch library system building is an important task to build a modern public cultural service system，and could countribute to the integration of public cultural resources，the improvement of public cultural services efficiency，and the extension of high quality resources to the grassroots level.In 2011，Hai'an County Library began the construction of the general-branch system；in 2015，Hai'an County officially launched the provincial public cultural demonstration area project，which created an opportunity for the development of the county general-branch library construction.This paper explains the practical development of the general-branch library construction and puts forward some suggestions and thoughts on the sustainable development of the county general-branch system represented by Hai'an county library.