Abstract:Combining the method of Analytic Hierachy Process with “mode and sum”, this study analyzed the change of the water environment carrying capacity(WECC)of the Three Diversions of the Jingjiang River after the operation of the Three Gorges Reservoir(TGR). The results show that: (1)before the operation of the TGR, the WECC of the Three Diversions of the Jingjiang River was between 0. 24-0. 36, which was in a weak level, and the carrying capacity was extremely fragile. In the space domain, the carrying level of Huarong was the highest, over 0. 30. The lowest was in Nanxian, less than 0. 29. (2)after the running of the TGR, the WECC of Huarong, Anxiang, Nanxian were increased respectively from 0. 32, 0. 38, 0. 27 in 2003 to 0. 42, 0. 40, 0. 40 in 2014. Before 2007, the WECC of Anxiang was higher than Huarong and Nanxian with considerable discrepancies between regions. After 2007, the carrying level of Huarong was at a slight advantage. With the increase of Nanxians WECC, the gap between various partitions was narrowed. (3)Compared with the WECC prior to operation of the TGR, the carrying level of each partition in the Three diversions of the Jingjiang River has been enhanced. The WECC of Huarong, Anxiang, Nanxian was increased respectively from 0. 32 to 0. 42, 0. 24 to 0. 40, 0. 26 to 0. 40, but had no big improvement, the water environment was still in a fragile state. (4)Under the operation of the TGR, the significant decline of water and sediment in the Three Diversions of the Jingjiang River has become the key factor of restricting the enhancing of the WECC in the Three Diversions of the Jingjiang River.