Abstract: [Purpose/significance] The purpose of this research is to clarify the functions and positioning of the subprovinciallibraries, and to provide a basis for the evaluation of public libraries, especially the establishment of evaluation indicators and scores for sub-provincial libraries. [Method/process] This paper reviews and analyzes the origin ofthe construction of sub-provincial cities, adopts a comparative analysis of the cultural industry standards of provincialand municipal libraries, and investigates the vision, functional orientation and goals of 15 sub-provincial libraries on theInternet. [Result/conclusion] The ten functional orientation of the sub-provincial libraries from three aspects includingpublic service, city assistance, and industry leadership is identified, namely civic lifelong education, civic cultural leisure, cultural co-construction and sharing, knowledge innovation support; urban information services, local cultural heritage, urban cultural landmarks, urban cultural empowerment; regional center coordination, industry business model.