Abstract: In recent years,affected by climate change,extreme rainstorm events occur frequently in urban areas of the Loess Plateau,causing many urban waterlogging and other water disasters,which seriously affects the social and economic development of the region. In this paper,the urban storm flood simulation model（Seorm Water Management Model,SWMM）is constructed in the gully region of the Loess Plateau to study the process of urban flood formation after the occurrence of extreme rainfall events with different design frequencies. The simulation results show that when the design return period of rainstorm is more than 2 years,some roads will be waterlogged,and the waterlogging will increase with the increase in the design return period. Affected by the buried depth,pipe diameter,number of inlets,topography,geology and other factors of drainage network,the runoff in some areas increases,and the flood overflow time and water depth increase. It is considered that the main causes of waterlogging in urban areas of the Loess Plateau have heavy rainstorm intensity,small infiltration and insufficient water collection capacity. In order to promote the construction of sponge city and improve the ability of flood control and disaster reduction,it is necessary to comprehensively consider the drainage status of the pipe network and the distribution of simulated ponding points,carry out the design and construction of drainage pipe networks of key ponding nodes,and promote the construction of sponge city.