The significant runoff changes forced by environment changes have brought new challenges for hydrology and water resources management.How to identify impacts of climate change and human activities to runoff change is a hot and difficult topic in hydrological science research.Firstly,the abrupt point of annual runoff time series is identified by comprehensive analysis based on STARS and Pettitt method and divided into natural and human activity period.Secondly,the hydrological model is built to simulate runoff process of natural period.Thirdly,the runoff processes of human activity period are simulated by the hydrological model.Lastly,the impact of environmental change on runoff change during human activity period is discussed under every decade and different year of precipitation frequency.The results show that the abrupt point from 1957 to 2014 is in 1992 for annual runoff time series of Xiangtan station in Xiangjiang Basin,there is very good agreement between measurements and calculations for natural runoff process based on Xinanjiang hydrological model,and the contribution rates of human activities and climate change to runoff change during human activity period are 68.24% and 31.76%,respectively,when the biggest times of climate change impact are in 20112014 but of human activity is in 20012010 especially at high precipitation year.