Flooding is one of the most common and serious natural disasters in China. Presently we usually simulate the most severe waterlogging during the rainfall process and lack the simulation technique for the whole rainfall process in the urban waterlogging simulation study. In this study, comprehensively using the SWMM model and GIS technology, by dividing the water catchment areas of the research area and modeling of the generalized drainage network, the SWMM model for the study area is established, and at the same time calculating the amount of water collected in the precipitation process based on the SWMM model, calculating the evolution of surface water by using the active diffusion algorithm. The simulation and simulation error analysis of the precipitation process in the research area on 18 June 2016 show that the method has good simulation effect.