Based on monitoring of pollutants in urban storm runoff in Zhuhai city, pollutant loads are calculated with the SCS hydrologic model, and the results of the calculations are considered. The results show that the annual mean value for runoff is 1529.2 mm，with of the highest values coming from traffic roads and commercial districts. The concentration of pollutants is high in the urban storm runoff. The pollutant loads for T-N，T-P，COD_Cr and BOD₅, are 765.27, 74.06. 11958.94 and 1104.71 t respectively. COD_Cr accounts for 72.32 percent of the pollutant load from industrial point sources (PS) and 24.69 percent of the load from non-point sources. Urban storm runoff makes water quality worsen rapidly within short time after rain. Consequently, urban storm runoff has a large impact on the water environment.