Abstract: Based on hydrological data from 1956-2008 of representative gauging stations, the evolution processes and its reason of annual runoff and sediment discharge in Zhicheng and Three Channels were investigated, using Mann- Kendall trend test and other analyses. The results showed that annual runoff of Zhicheng was relatively lower after 2003, which might be related to lower precipitation in the upper reaches of Yangtze River. However, this change was insignificant. Annual runoff in Zhicheng, annual runoff and sediment discharge in Three Channels, as a whole, were significantly decreasing tendency, and the abrupt time was 2003, 1979 and 1989, respectively. Annual runoff in Three Channels only had a turning point in 1973, while annual sediment discharge had two turning points in 1973 and 2003, respectively. Turning point in 1973 was primarily caused through decreased runoff by the cutoff in Jingjiang River, and the turning point in 2003 was mainly caused through decreased suspended sediment concentration by the running of Three George Reservior