In recent years, under the influence of global climate change, extreme weather such as super rainfall has increased, and Ruijin city has frequently suffered from large floods, which seriously affected the social and economic development of the city. Based on the two major flood events of "2019.7.14" and "2022.6.13" in Ruijin city in recent years, this paper fully analyzes the benefits of urban flood control by Ridong reservoir, located at the urban upstream as a flood control hub, and extracts relevant improvement measures from the aspect of important roles in flood control and disaster reduction played by the control hub. The results can provide reference for other related types of cities.