Based on runoff and sediment series data of nearly 60 years from 4 representative stations of Ji-an, Xiajiang, Zhangshu and Waizhou in the middle and lower reaches of the Ganjiang River, this paper analyzed the temporal and spatial distribution characteristics of runoff and sediment discharge. The results show that the annual runoff in the middle and lower reaches indicates a weak increase tendency. Affected by the Wanan Reservoir operation, the concentration degree of flood season runoff had a slight decrease after 1990; There were no obvious change of the annual sediment discharge at the various stations from 1950s to 1980s, while there has been an obvious decline trend since 1990s, and there is correlation between the decline scale and distance from the reservoir for the various stations.