Abstract: From August 9 to 10 of 2024, a short-term heavy rainstorm occurred in the Juhe River, and the flood peak flow of Yangzhuang Reservoir in Tianjin City reached the historical maximum of 1 100 m³/s. In this paper, based on the analysis of the characteristics of the rainstorm and flood characteristics, the hydrological and hydrodynamic models are constructed based on CNFF and IFMS/Urbans to simulate the rainstorm and flood process. The results show that: the return period of rainfall is 20～50 years, the return period of flood peak flow is 10～20 years, and the maximum discharge flow is 500 m³/s; The flood dispatching process effectively reduced the upstream flood peak by more than 50%, and there was no superposition of the maximum outflow and the flood peak, which gave full play to the flood control role of Yangzhuang Reservoir; River flood analysis and ground inundation analysis simulation are basically consistent with hydrological observation and field investigation. It is suggested that the reservoir should adopt the pre-discharge method in combination with the weather forecast during flood seasons, reduce the water level of the reservoir in advance, and control the discharge as far as possible at 300 m³/s and below. The research results can provide reference for flood forecasting and flood operation of Yangzhuang Reservoir.