Abstract: Aiming at the social questions on the prevention strategies after the "2021.7.20" urban flood in Zhengzhou,this paper explains basic concepts of flood control and drainage systems in urban area and analyzes the effect of low-impact development systems in sponge city construction of Shenzhen. Moreover, the paper introduces the basic countermeasures of rainstorm disasters in Tokyo,Japan and the prevention system of flood(tide) in Shenzhen as a socialist pioneering demonstration area in China. The paper could provide reference for the other cities in our country to formulate the prevention strategies of urban flood and to define the development directions in the future.