Abstract:Taking the Qujiang River Basin above the Quzhou Hydrological Station as the study site, the characteristics of the annual runoff and sediment load during the period from 1958 to 2006 were analyzed based on the hydro-data of the Quzhou Hydrological Station. The variation trends and features of runoff and sediment load in the study period were investigated using the Mann-Kendall trend test, Sen s slope method, cumulative filter method, and double mass curve method, and the influencing factors were analyzed. The results indicate that there was no significant change in the time series of annual runoff, while the runoff in the dry season(from August to January of the next year)showed a significant increasing trend and the runoff in the flood season(in May)showed a significant decreasing trend. The annual sediment load had shown a significant decreasing trend since 1980. The major factors correlated with the runoff and sediment load changes such as precipitation, sediment detention in reservoirs, and soil conservation were also analyzed. Water replenishing and regulating from the reservoirs in the Qujiang River Basin might cause the changes of runoff. The construction of reservoirs and implementation of soil conservation measures were the main factors that resulted in the decrease of sediment load in the basin.