Abstract: In this paper, according to the rule of unbalanced sediment transport andthe analysis of field data, different water diversion schemeswere theoretically studied, including the erosion and sedimentation trend as well as their impacts on the environment of the middle and lower reaches of the Hanjiang River. The results showed that the 95108m3water diversion scheme will cause less erosion and water level decrease than the 15108m3water diversion scheme. Using a water diversion scheme of 95108m3, the decrease of water quantity can impact the river hydrodynamic regime substantially andthe environments of the middle and lower reaches of the Hanjiang River will be greatly affected. It is therefore necessary to develop new water resources or build projects to meet the need of the environment and the needs for navigation.