Abstract: Aiming to investigate the influence of design storm pattern on urban flood inundation, this work applies a numerical model to simulate the hydrological and hydrodynamic processes and analyze urban flood inundation patterns in Xi'an New Area, Shaanxi Province, China. Design hyetographs with different position coefficients for the storm peak and return period are considered. By comparing the simulation results in terms of water depth and inundation extent, it is found that the lower position coefficients of storm peak with the return period less than 20 a may cause more total inundation, but opposite conclusion may be drawn for the storms with the return period greater than 20 a. Apart from the return period of 2 a, the storms with a higher position coefficient of storm peak will result in more total inundation, but the more serious Ⅳ-level inundation is reduced. With a lower position coefficient of storm peak and longer return period, the lag between the times to the peak inundation and to the storm peak becomes bigger. This work demonstrates quantitatively the effects of design storm pattern on urban flood inundation. The research may help make more informed decisions on urban flood management.