Abstract: With development of urban transportation industry, traffic jams have been significantly alleviated through construction of urban interchange bridges. Unfortunately, around an undercrossing overpass, relatively low areas are shaped due to the elevation of its roadway lower than those of the surrounding ground, and during a rainstorm waterlogging often occurs and may pose a grave threat to the publics and traffics. Simulations and analysis of the waterlogging depth and velocity in this case are crucially significant to reduce flood disaster and traffic emergency. This paper presents MIKE21 Flow Model simulations of waterlogging depth and velocity for the rainstorm events of different precipitation frequencies over the Lianghua bridge area. Analysis of the rainstorm on July 21st, 2012 shows that the calculated waterlogging depths agree with the in-situ observation. In this study, a modeling technique is developed for simulating waterlogging conditions in relatively small city areas, aimed at providing a technical support to waterlogging simulations for the areas lacking data of good accuracy.