Abstract: In the flood season of 2020, heavy rains and floods occurred frequently in the upper reaches of the Yangtze River, and the amount of sand entering the Three Gorges Reservoir had increased significantly with annual amount of 194 million t. We first systematically analyze the features of water and sand variation in upper reaches of Changjiang River, and point out the new characteristics of sediment deposition of Three Gorges Reservoir in 2020: the amount of sediment deposition in the reservoir area was significantly larger than that in previous years. At the same time, the reservoir tail and flood control storage capacity had obvious deposition. Among them, the river section above Tongluoxia had changed from previous erosion to deposition with volume of 3.53 million m3, accounting for 3% of the total deposition volume in the Three Gorges Reservoir area; the Three Gorges Reservoir suffered the highest deposition of 24.4 million m3 in its flood control storage capacity since the 175m pilot impoundment; and the deposition intensity in front of the dam had increased significantly. Based on the systematic analysis on characteristics of water and sediment changes in the upper reaches of the Yangtze River, we summarize reasons of sedimentation in the Three Gorges Reservoir area in 2020, namely the heavy rain-induced sand yield in upper tributaries, such as Jialing River and Minjiang River, and the higher water level in front of dam site due to flood retention operation. The results provide more powerful technical support for the scientific operation of the Three Gorges Reservoir.