In the process of rapid urban expansion, flooding has become a common problem in cities with flat terrain. This is due to the high volume and intensity of rainstorms, which has exceeded the drainage capacity of the existing municipal rainwater channels. Proposal has been made to divide large-area drainage into small-area drainage, disperse the discharge and add a self-controlled drainage pump to solve the problem of internal defects of the old city. At the same time, the new urban area will establish different rainstorm return periods according to the level of the road, build large underground storage tanks and rainwater pumping stations, and combine the newly proposed sponge city construction theory and deep water storage technology to retain and use part of the rainwater. At the same time, the siltation of dredged rivers and lakes will be increased and regional flood scientific dispatch during heavy rains will be implemented to improve the city's ability to resist heavy rains.