Focusing on the quantitative identification of the impacts of climate change and human activities on annual and maximum daily runoff at a basin scale,taking the Wujiang River Basin,South China for instance,this paper simulated and quantitatively evaluated the impacts of climate change and human activities on runoff and their contribution ratios to runoff at daily and annual scales by using the HIMS model and elastic coefficient method.The results showed that,the HIMS model performed well in the Wujiang River Basin at daily scale.The Nash-Sutcliffe coefficients are 0.85 and 0.77,and the absolute values of water balance errors are 3.1% and 3.3% respectively in calibration and validation periods.The results obtained by the HIMS model and the elastic coefficient method indicated that climate change is the dominat factor that leads to the increase of annual runoff and human activities cause the runoff decrease while its contribution ratio is smaller compared to that of climate change.The annual maximum daily runoff showed an upward trend due to climate change and human activities.The contribution ratios of climate change and human activities are 94% and 6%,respectively.Climate change has greater impact on annual maximum daily runoff than that on annual average runoff.