The typical Wangjiaqiao watershed within the Three Gorges Reservoir area was selected as case study to investigate thevariation of runoff under the changes of land use, climate and the combination of them by using the soil and water assessment tool(SWAT) for simulation. The results show that the rates of annual average runoff change by 15.13%, －13.99% and 23.22% underthe scenarios of arable land expansion, returning farmland to forest and economic forest development respectively. Furthermore,returning farmland to forest can regulate and reduce runoff. Under the climate scenarios of RCP 2.6, RCP 4.5 and RCP 8.5, thechange rates of runoff are 7.13%, 7.78% and 8.91% respectively,and the runoff increase with the future emission of greenhousegases and sulphate aerosols. The annual average runoff increase greatly under the scenario of the combination of them,especiallyaround 2030. In addition,the variance analysis has found that the influence of land use are more significant than that of climatechange on runoff. It is advisable that land use in the watershed can be allocated reasonably to control water balance in the future.