Abstract: Historical flood process, flood characteristics and precipitation characteristics of Fushui River reservoir upstream were analyzedby using historical disaster analysis, statistical method, and hydrological and hydrodynamic models.Based on the biggest flood-inducing precipitation sequence, different return periods of surface precipitations at upstream were obtained by using Gumbel extreme value type I distribution method.Based on the rainfall-induced flood flow line of annual frequency simulated by using Xin'anjiang model, downstream floodrisk was analyzed, and the flood situation of dike-break risk was also analyzed by using hydrodynamic model.The results show that rainfall-induced flood accounted for 77% of the total process.Rainstorm process of rainfall-induced flood was mainly regional heavy rain.Theflood caused by 100-year return period rainstorm process can make the water level exceed the maximum water level record.In the design ofthe breach, some villages and towns in Yangxin county have the risk of flooding.