Abstract: In this study, rainfall runoff events are monitored in a subway depot in Beijing, by event mean concentration (EMC) and cumulative pollutant quality-cumulative runoff curve (M (v) curve)． Significant differences were noted in suspended solids (SS), chemical oxygen demand (COD), ammonia nitrogen (\mathrmNH^+_4 -N) and total phosphorus (TP) concentrations in the runoff of different underlying surfaces of a subway car depot (P < 0.05)． Initial erosion intensity of the drainage area dominated by building roof was stronger than that dominated by track． Based on SWMM model, parameters and spatial distribution of rainwater storage tank in the study area were adjusted． Further analysis showed that decentralized design of rainwater storage tank could further reduce drainage volume and improve water quality of the drainage and storage tank, thus reducing treatment difficulty and cost of rainwater reuse． These data can provide some reference for optimizing design of stormwater storage tank and improving control and utilization of stormwater．