Abstract: In recent years, due to the frequent occurrence of extreme rainstorms and the high population density, the infrastructure of the city cannot keep up with the development needs. The high density of population increases the sensitivity of cities to disaster-causing factors, resulting in greater losses in cities when disasters occur. How to optimize the resilience of cities, reduce disaster losses caused by extreme rainstorms, and enhance the ability of cities to withstand disasters, and make the problem of rapid restoration of city after disasters urgently needed to be resolved. This article analyzes the vulnerability of the number of people affected, economic losses, and infrastructure in high population density cities. And then from the optimization of sponge city construction, flood control standards, urban infrastructure, disaster early warning and facility digitization to improve the resilience of high-density cities after disasters to respond to and adapt to disasters. Resilience can effectively reduce the degree of disasters, so that high-density cities can "retract and unwind freely" in the face of extreme rainstorms.