Abstract: Based on the "2021.7.20" extreme rainstorm in Zhengzhou City,the rainstorm scenario with the same intensity was transplanted to Kunming City, Yunnan Province, and the urban flood model was used to simulate the flood situation in Kunming urban areas. The results show that the main rivers in the urban area overflowed in different degrees and most urban areas ponded with a depth of more than 0.15 m with a total of 821 waterlogging points, of which 89 waterlogging points with a water depth more than 2.00 m, and 195 waterlogging points with a water depth of 1.00~2.00 m. The main roads were seriously flooded, some of which with the depth exceeding 2.00 m. The analysis results show that the extreme rainstorm far exceeds the normal drainage capacity of the city,and flood disaster is unavoidable. According to the results of simulation analysis,together with the status quo of the flood projects,it is proposed to improve the flood control and drainage engineering system in Kunming with systematic management ideas,highlight the "four preplans" (forecast,early warning,prerehearsal and preplan) to strengthen the construction of the flood control emergency response system in Kunming, and improve residents'awareness of disaster prevention and self-rescue capabilities to deal with extreme rainstorms. Related analysis and suggestions can provide reference for other cities.