| The erosion development of the channel downstream of the Three Gorges Dam (TGD) affects the flood control, navigation and economic development of the middle and lower reaches of the Yangtze River. However, the quantitative research on the temporal and spatial evolution of the erosion center (i.e. the reach with high erosion intensity) in the downstream of the dam is still insufficient at present. Based on the data of water discharge, sediment load, bed material size and cross-sectional surveys, we analyzed the vertical, lateral and bankfull channel geometry changes in the Yichang-Chenglingji Reach (about 400 km) downstream of the TGD. The channel was divided into 32 sub-reaches according to the planform and the changes in bankfull area and bankfull depth were classified into different levels. A spatial clustering analysis method was introduced to study the distribution of the sub-reaches with highest erosion level and analyze the migration characteristics of the erosion centers. The result indicated that, temporally, the channel downstream of the TGD experienced fairly strong erosion during the initial impoundment of the Three Gorges Reservoir (from 2003-2007), weakened erosion after the reservoir was operated with normal pool level of 175 m (2008-2012), and then, enhanced erosion after the cascade reservoirs upstream of the TGD started to operate (2012-2018). Spatially, upstream sub-reaches were generally eroded while transition between degradation and aggradation was common at the downstream reaches. The meandering lower Jingjiang reach was generally in the 4th zone, where the channel degradation and aggradation alternated frequently, but the degradation and aggradation rates decayed as time elapsed. The erosion centers tended to migrate downstream and the migrating rate of the erosion center was fast during the initial operation period of the TGD, then slowed down, accelerated following the operation of the cascade reservoirs upstream of the TGD, and slowed again a few years later. The average migrating rate of the erosion center during 2003-2018 was 7.5km/a.