Abstract: Happy rivers explains the connotation of "Comprehensive consideration and measures in water conservancy" and also puts forward more clear requirements for the management of urban rivers. However, there are often conflicts among the goals of urban water security, water landscape, water ecology and so on. It is inevitable to have adverse effects on water landscape and water ecology while the flood regulation function is brought into play. It is a common problem faced by cities in China that "Looking at the sea in the city" and "Water pollution after rain". Taking Qingshan Lake drainage area of Nanchang City as an Example, this paper analyzes the present situation faced by the operation dispatching of urban waterlogging prevention system, researches the existing problems and causes, and then puts forward optimization principles and paths based on the results of numerical simulation of urban storms and floods. The primary conclusions are:First, "Dynamic control of Rainstorm in the whole process" is helpful for the "multi-objective" coordination in the operation of urban waterlogging prevention system. Secondly, under the numerical simulation of urban flood, the influence of different scenarios on urban water system can be predicted more scientifically, which is helpful to delimit the key objectives at different stages according to the principle of "grading and timeshare", and then determine the control timing and threshold of water level reasonably.