Since the 175 m tiral impoundment of the Three Gorges Reservoir，the amount of sand entering the reservoir has been greatly reduced，and there is a certain difference between the sediment scouring and silting characteristics of the reservoir and the research achievements in the argumentation stage. In response to this problem，based on the prototype observation data of sediment in the channel of the Three Gorges Reservoir since the impoundment of the Three Gorges Reservoir，we systematic analysis the characteristics of inflow-outflow of the water-sediment characteristics，and the sediment scouring and silting situation in the reservoir area and the sediment deposition distribution. The results show that：1）The amount of sand entering the reservoir is significantly reduced than expected. 2）The siltation is mainly concentrated in the perennial backwater area below Qingxichang，and the river sections with a large amount of siltation and strong siltation intensity are mainly open and branched river sections in the perennial backwater area. 3）Sediment silting presents the characteristics of flat silting in main channel and asymmetric siltation dominated by siltation on one side.