Sediment problem is one key technical issue in the construction and operation of the Three Gorges Project. Only by properly handling the sediment problem can we ensure the long-term effective use of the Three Gorges Project and maintain a full play of the reservoir function. In this paper, the characteristics of sediment deposition and the sediment discharge ratio of the Three Gorges Reservoir (TGR) in the past 20 years have been comprehensively analyzed and studied based on the observed hydrological and river topographic data, and compared with the existing research results; Secondly, the influence of reservoir sedimentation is further analyzed in terms of flood control, navigation and sediment deposition in front of the dam. The results show that since the TGR impoundment, the total sediment deposition of the TGR is 2.0484 billion tons, approximately 110.2 million tons per year, the sediment discharge ratio of the reservoir is 23.6%, and the average annual sediment deposition of the reservoir is 33% of the original demonstration prediction value without considering the sediment from the interval. Among them, the accumulated sediment deposition in the main stream section of the reservoir area is 1.7835 billion m³ (69.4 million m³ scoured by the fluctuating backwater area; 1.8529 billion m³ silted by the perennial backwater area), and the sediment deposition in the reservoir flood control storage capacity is 164.8 million m³ (151.7 million m³ silted by the main stream and 13.1 million m³ silted by the tributary respectively), accounting for 0.74% of the reservoir flood control storage capacity. The average annual sediment deposition and sediment discharge measured during the 11th Five Year Plan period are relatively large, the scouring and silting in the fluctuating backwater area are reversed, mainly due to the influence of the large amount of sediment entering the reservoir, the recent sand mining in the river channel and the optimal operation of the reservoir. The influence of reservoir siltation on flood control storage capacity and underground power plant is still small, and it has a certain impact on some waterway conditions in the reservoir area, which should be paid attention to.