As the first inter-provincial metropolitan area in China, how to promote the integration of social governance in administratively adjacent areas is an important issue in the construction of the Nanjing metropolitan area. Promoting the integration of social governance in adjacent areas is of great significance to the implementation of national development strategies, the promotion of coordinated regional development, the promotion of public affairs governance, and the realization of social integration and co-promotion. By analyzing the case study of “Pukou-Hexian” social governance integration in Nanjing metropolitan area, it is believed that it has formed good practical experience in leading governance cooperation through Party building, building technical platforms, and improving operational mechanisms. The main reason is that Pukou and Hexian have the same historical and cultural basis for governance, face common social problems in terms of governance needs, and follow multiple operational logics in terms of governance mechanisms. Through the above analysis, it is believed that a systematic thinking approach should be adopted, based on the strategic height of the Yangtze River Delta integration and the high-quality development of the Nanjing metropolitan area, to collaboratively promote the integration of social governance in administratively adjacent areas at six levels, including planning, team building, data governance, platform building, subject participation, and cultural identity. And it is proposed that cross-border coordination plans should be formulated, professional talent teams should be formed, data governance should be continuously strengthened, governance entities should be established, participation of multiple subjects should be encouraged, and cross-district cultural exchanges should be enhanced, so as to ultimately realize the form of social governance integration with “no vertical linkage and no horizontal synergy”.