With the development of digital cities and smart cities, urban simulation has developed from two-dimensional to three-dimensional. Urban three-dimensional real-world modeling becomes more and more challenging. Due to the high density and rapid change of urban features, traditional manual 3D modeling methods are inefficient and cannot adapt to the rapidly changing urban environment. Therefore, UAV tilt photography technology is often used for fast 3D modeling. However, UAV tilt photography method cannot solve the problems of urban object occlusion, canopy occlusion, eaves occlusion, glass light transmission, etc., resulting in defects in the 3D model, such as local texture distortion, object pulling, and object voids. To dealing with these issues, taking the campus of University of Chinese Academy of Sciences as the research area, a fusion modeling method was proposed by combining the UAV tilt photography technology with ground LIDAR technology. In the experiment, a drone image acquisition strategy of "regular route mainly automatic shooting-based, supplemented by interest area with manual shooting" was used in the field; in interior work, "manual coarse registration and ICP algorithm fine registration" was used. The experimental results show that the method of multi-source data fusion can not only ensure the efficiency of 3D modeling, but also solve the problems of ground distortion and holes in the UAV alone modeling method, improving the accuracy of the model, and optimizing the 3D model of the city.