Abstract: A heavy precipitation which is rare in history struck Datong river basin from 20 BT 5 July to 20 BT 6 July 2013. By using data of hourly rainfall with all of the meteorological stations in the basin, the cumulative rainfall as well as the forecast precipitation, the digital elevation model, the landuse, the soil types and the disasters data etc, this study adopts one of the flooding scenes - the rainstorm flooding of FloodArea model, to carry out the flooding simulation of this heavy precipitation and to test its effectiveness. The results show that there is a sharp rise of the water level at upper and middle of Datong river basin, and the water level has increased by over one meter in most parts, by over 3 meters in some branches and by 6 meters in some areas in Zhuyang town, Youhua town and Qiaomu town. According to the disaster investigation, in both the aspects of flooding scope and flooding depth, the simulation result of FloodArea model agrees with the fact. This indicates that the FloodArea model generates good simulation effect of flooding in Datong river basin and it can be employed in the risk evaluation and early-warning of rainstorm and flood disasters.