Abstract: Climate change and human activities have had significant impacts on the hydrological cycle, especially in arid and semi-arid zones. In order to investigate the evolution characteristics of the hydrological cycle in a typical semi-arid ecologically fragile area which is the Us Sandy Land under changing environment, this study based on WEP-L (Water and Energy transfer Processes in Large river basin) surface water model and Visual MODFLOW (Visual Modular Finite Difference Groundwater Flow) groundwater model simulate water cycle process in the Us Sandy Land and the model parameters are calibrated and validated based on the measured monthly runoff from Baijiachuan hydrological station and groundwater level data from monitoring wells. The results show that the correlation coefficient between the simulated and measured monthly runoff in the surface water model calibration period and validation period are above 0.5, and the trends of the simulated and measured groundwater levels in the monitoring wells are more consistent with each other, with a correlation coefficient of more than 0.56. The bias-corrected CMIP6 multi-model ensemble climate change scenario and the local water withdrawal scenario were used to drive the coupled surface water-groundwater model to quantify the characteristics of the changes of key water cycle elements in the Us Sandy Land under changing environments from 2021 to 2040. The results show that in the future scenario the average increase of annual precipitation and annual evapotranspiration in the Mu Us Sandy Land is 8% and 7.4% respectively, and the depth of annual runoff is in a gradual decreasing trend. Meanwhile, the groundwater level at the end of 2040 decreases about 1 m compared with that at the end of 2021.The difference between the total regional groundwater recharge and discharge under the two water use scenarios in the future is −1.82 million m³/a and −0.097 billion m³/a, and the difference between total surface runoff and surface water use is 1.83 million m³/a and 2.29 million m³/a. It indicates that the development and utilization of groundwater resources will face greater challenges. This study can provide scientific support for the regional water resources planning and management in the Us Sandy Land.