••Develop a building-level RSPV potential assessment model for mega-cities••. Rooftop solar photovoltaics (RSPV) are critical for megacities to achieve low-carbon. As the world's largest CO2 emitting country, China accounts for about 28.8% of global carbon emissions (British Petroleum, 2020). Decarbonization of China's economy is pivotal in realiz. Potential for rooftop solar photovoltaics powerBeijing GM area (inside RD6), which accounts for 80.2% of population and 13.8% of the juris. Author contributionsConceptualization, M.S., X.L., and A.F.; Methodology, M.S., H.J., S.C., N.Z., and Y.W.; Investigation, M.S. and Q.M.; Writing – Original Draft,. The following references appear in the Supplemental information: Abu-Hamdeh and Taherian, 2015, Anjuke, 2022, Author Anonymous, 2020, Dulac and Hu, 2019, Fan et al., 2015,.