Abstract: Urban rainstorms and waterlogging disasters are the most prominent disasters in cities. An extremely heavy rainstorm occurred in Shenzhen on Sep. 7, 2023. The Shenzhen River Watershed locates at the center of the rainstorm, and suffers significant flood disaster. The rainstorm flood disaster sounded the alarm for the water security of the city. Based on the summary of characteristics and prevention of rainstorm and flood in the Shenzhen River Watershed, the causes of rainstorm and flood disasters are analyzed. Furthermore, strategies are proposed from the aspects of improving the flood discharge capacity of river channels, increasing the flood storage capacity of the watershed, strengthening the construction of urban drainage and flood prevention capacity, and improving the emergency management capacity of the rainstorms beyond designed standard. Then, thinkings on the urban flood control methods and concepts are presented. It provides a reference for solving the flood problem and improving the flood prevention capability of high-density cities.