In recent years, the construction technology of urban 3D models has been applied to the planning and research of numerous “digital cities” and key urban areas, greatly improving the visualization and data field calculation capabilities of resource survey and monitoring results. Based on the integration technology of multi-source data, this article proposes a general framework for the construction of an integrated 3D model of aboveground and underground areas. Key technologies such as data storage, network transmission, and spatial topology optimization are studied, and an integrated 3D model of aboveground and underground areas in the southwest third ring road area of Beijing is constructed unify and transform multi-source 3D data through data standardization processing, and use AI technology and wavelet transform algorithms for integrated storage, management, and transmission The surface scene model and 3D geological model are combined and preprocessed using the benchmark drilling vector as the vertical ruler of the stratum optimize and adjust the spatial topology errors that exist in the overall and unit regions during the model integration process, solve the connection problem between spatial models, and improve the accuracy of integrated integration.