Abstract: For urban waterlogging caused by torrential rain in highly built-up areas of plain cities, a coupling model of urban waterlogging was constructed by using MIKE URBAN,MIKE 11 and MIKE 21 based on the MIKE FLOOD platform.Taking Dongguan City in Pearl River Delta as an example, a new long-duration designed storm was proposed based on historical rainstorm events to analyze the process of urban waterlogging and characteristics of flood inundation in the central urban area of Dongguan City under 50-year designed storm scenarios.Measures to improve the drainage capacity of "major drainage system" were suggested, and its effectiveness was evaluated.The results showed that the main causes of urban waterlogging in the central urban area of Dongguan City were river water jacking and poor road drainage.Combining river channel widening and road vertical adjustment could reduce the overflow volume of the pipe network by 45% and decrease waterlogging area by 73%.Improving the drainage capacity of "major drainage systems" such as rivers and road drainage channels has a significant effect on improving the waterlogging situation.The research results can provide technical support for the management of waterlogging in highly built-up areas of plain cities.