In July 2020, Capinfo won the bid on the pilot project of Beijing City Brain to support and lead the construction of the city brain. According to the requirements for top-down planning of the municipal city brain system, we were fully responsible for top-down planning and design of Beijing City Brain. By comprehensively analyzing design proposals for all streets of Beijing, talking part in special seminars and conducting field surveys, we actively output proposals for constructing street-level city brains. Gradually, we established a mechanism for interfacing all big data platforms and grassroots business applications of Beijing. We explored how to offer feedbacks about operation status of grassroots cities in municipal leaders’ cabs, construction and operation modes of city brain systems. We built data bases for grassroots brains and provided “data” resources for governance and construction of grassroots cities. Based on this project, we have created “reproducible and propagable” Huitian Brain with space for growth for Changping District, to effectively improve government work efficiency.