Population is the core resource of urban development and the main body of urban services. As a large city and the center of the Beijing-Tianjin-Hebei metropolitan area，Beijing has a huge floating population and complex management. It can grasp the population and structure changes in the city in real time. Provide scientific basis for urban development and management. China’s population statistics are based on the decennial population census，and the non-census year population sample survey is the main survey system. With the advancement of technology and the changes in the actual needs of population development，the content and methods of the census should be optimized accordingly. Adjust，learn from the American smart city，the British population database and the combined mode census and other international advanced experience and technologies，use the development advantages of big data technology to solve the technical problems of the census，and improve the application efficiency of the census in the comprehensive management of mega cities.