Abstract:Accurate identification of urban functional areas helps refine urban management and rationalize resource allocation. Traditional methods of urban functional area identification rely heavily on field research and statistical yearbook data, which are inevitably subjective and limited by the tediousness of data acquisition, resulting in a timeconsuming and inefficient identification process. The wide application of geographic big data provides a new method and approach for urban research, and has been used to assist urban planning and construction and management. In order to promote and popularize the application of geographic big data in urban functional area identification, megacities are taken as the research object and accurately identifies various types of major functional areas in the study area based on geographic big data, such as OSM (Open Street Map) road network and internet location information, and compares and verifies the identification results with the real city scenery. The experimental results show that the spatial and temporal scale analysis based on geographic big data combined with regional activity indexes can accurately identify the main functional areas in line with the current planning status of megacities, which proves the effectiveness of the identification of urban functional areas supported by geographic big data and helps to provide references for the efficient implementation of urban planning and construction management and other related work.