To understand the influence of water and sediment conditions on scouring and silting characteristics of the Dahukou River,based on a two-dimensional numerical model of water and sediment, the scouring and silting of the river reach under different water and sediment conditions in typical years of flood, normal and dry were simulated, and the changes of sediment scouring and silting and river morphology variation were analyzed. The results show that the original scouring and silting of the Dahukou River is represented by the first, second and fourth sections of silting, and the third section of scouring. The change of water and sediment conditions makes the riverbed scouring and silting of the Dahukou River generally show the trend of silting upstream and scouring downstream. The scouring and silting of the river section are characterized by silting along the left bank and scouring along the right bank with enhanced degree of scouring and silting. With the change of incoming water and sediment in the upstream, the Dahukou River gradually evolves into a single and curved channel, which may have certain impacts on the flood control. Keywords: water and sediment conditions;river morphology variation;river scouring and silting; Dahukou River 〖FL