Abstract: Wulongkou parking lot is located in the drainage area of Wulongkou open ditch of Jialu River Basin in Zhengzhou City, and the waterlogged water of the drainage area is mainly discharged through Wulongkou open ditch. After field investigation and data analysis, the terrain of Wulongkou parking lot is significantly lower than the surrounding roads and blocks. The ponding of the parking lot area in the "7·20" heavy rainstorm is mainly from the parking lot area and the upstream catchment area of the starting point of the open ditch. The waterlogging analysis model of Wulongkou parking lot is constructed, which is composed of 2D surface hydrodynamic model of Wulongkou open ditch drainage range, 1D hydrodynamic model of Wulongkou open ditch and subway tunnel flooding model. The rationality of the model is analyzed by using the "7·20" flood investigation results in Zhengzhou City. In order to analyze the impact of the collapse of the retaining wall of Wulongkou parking lot, the soil pile on the west side of Wulongkou open ditch and the starting cover plate of the open channel on the waterlogging in Wulongkou parking lot and its surroundings and the subway tunnel flooding, the waterlogging analysis model of Wulongkou parking lot is used to simulate and analyze four calculation scenarios. The calculation results show that if there is no temporary soil pile and cover plate near the starting point of Wulongkou open ditch, and the retaining wall of Wulongkou parking lot does not collapse, the maximum ponding depth at the intersection of Huanbao road and Lantian road can be reduced by 0.35 cm. The maximum inflow of the subway tunnel entering and leaving of the Wulongkou parking lot can be reduced by some 50%, and the total inflow can be reduced by some 60%