Administrative division adjustment is a policy arrangement by the government to change the trajectory of urban development and reshape the urban development dynamics and regional development pattern. Currently，promoting urban-rural coordination and accelerating urban-rural integration are main objectives of administrative division adjustment. Administrative division adjustment can reduce administrative costs，optimize resource allocation，and improve the conflict between supply and demand of public services. Meanwhile，it also affects the supply-demand structure of public resources and the spatial layout of public service facilities. This paper is a case study of Chengdu that discusses the relationship between administrative division adjustment and changes in public service supply system in Chengdu from the longitudinal historical trajectory. It also explores the specific mechanism of public services and explains the dual effects of administrative division adjustment on public service supply.