After the operation of the Three Gorges Project (TGP), the sandbars in the middle and lower reaches of the Yangtze River were scoured and atrophic mostly, resulting in the channel conditions extremely unstable. In order to explore the dominant factors affecting the evolution of sandbars, combined with the recent hydrologic, sediment, and topographic observation data, the Guangxingzhou point bar of Tiepu reach of the lower Jingjiang is taken as an example to analyze the adjustment characteristics of sandbars and their response to boundary conditions, flow and sediment processes and remediation projects. The results show that most of the fine sand in the composition of the sandbars are weak in resistance to erosion, which is the precondition for the erosion of sandbars. After the operation of the TGP, the Guangxingzhou point bar has a tendency of erosion and shrinkage year by year. The change of flow and sediment conditions is the dominant factor of the deformation of the sandbars, there is a relationship between the variation of the Guangxingzhou point bar and over-bar discharge (Q>15000 m³/s), and the longer days last, generally the smaller the sandbar is. The amount of bed material in flood season is greatly reduced, especially the decrease of fine sand (0.125 mm<d<0.25 mm), making the point bar shrink significantly, the impact of which is greater than over-bar discharge. There is a significant correlation between the area of the Guangxingzhou point bar and the average fluvial erosion intensity of over-bar disscharge in the first three years. After the implementation of the revetment project, the receding trend of the point bar is restrained, the area is stable and increased slightly, indicating that the revetment project has been fully effective.