The distribution and construction of urban drainage network is an important part of urban infrastructure construction, and the drainage capacity of the city is related to the normal operation of urban service function. Urban flood disaster can be evaluated through the analysis of urban flood process. The MIKE URBAN was used to construct a model of pipe drainage network to assess the drainage capacity of the central urban area of Xi'an City based on the simulation results and to analyze the causes of waterlogging. The results showed that MIKE URBAN can simulate the distribution of water level, flow rate and waterlogging point in urban pipeline network. According to the formula of rainstorm intensity in Xi ' an, the rainfall process of different return periods (1a, 2a, 3a, 5a) was designed. Under the process of 1a rainfall, more than 90% of the pipeline in the research area is in full flow state, and more than 60% of the inspection wells overflow, and the number of full flow pipes and overflow wells will increase with the increase of rainfall frequency, but the increase speed is relatively reduced. The general low pipeline design standards, the increase of impermeable rate of the underlay surface, topography and other factors are the main causes of water accumulation on the ground. The research results can provide theoretical basis and technical support for urban waterlogging control and Sponge city construction.