Based on a new land surface model CLM_CERES,spatio- temporal changes in evapotranspiration(ET)in three typical mountains of China (Taihang Mountain,Hengduan Mountain,and Qiangui Karst Mountain)in baseline of 1951-2005 and estimation period of 2006-2060 were simulated. The CLM_CERES model was constructed by considering the scheme of water exploitation and utilization,and coupled with the crop growth and development model CERES. This new land surface model was driven by the atmosphere external forcing data of multimodel ensemble data of CMIP5. The simulated results were validated with a data-driven estimate of global land evapotranspiration(MTE data)derived from observations from a global network of micrometeorological tower sites (FLUXNET). The results showed that ET simulated by CLM_CERES was consistent with the MTE data among all three regions at a monthly scale(R2=0.76~0.88). From 1951 to 2060,the total ET increased significantly with linear trends of 0.981 and0.757 mm/a(P < 0.001)over Taihang Mountain and Hengduan Mountain,of which vegetation ET dominated. However,the total ET increased insignificantly over Qiangui Karst Mountain,of which soil evaporation dominated. Intra- annual variation of ET in all three regions from 1951 to 2060 showed unimodal curves with a peak region from May to September. The spatial distribution of ET was mainly influenced by climate change and topographic factors over Taihang Mountain and Hengduan Mountain. The spatial distribution of ET over Qiangui Karst Mountain was more complex due to the particularity of dualistic structure between surface and ground water.