Based on regional water balance theory and SWAT model, the construction idea of distributed water budget balance model and calculation method of water budget balance were proposed. The water budget balance of the Qinhe River Basin was simulated under human activities and future climate change, and the main factors affecting the water budget balance and its evolution patterns were analyzed with the Pearson correlation coefficient and Mann-Kendall test method. The results show that the total water storage in the Qinhe River Basin decreased from 2010 to 2016, and precipitation and outlet runoff are the key factors affecting the water budget balance in the Qinhe River Basin. In the future, the total water storage will increase under multiple climate scenarios, and the overall changes of annual mean precipitation and outlet runoff are positively correlated with the radiative forcing level. Under the typical climate scenario SSP2-4.5, the precipitation and outlet runoff may have abrupt changes from 2037 to 2041 and from 2061 to 2063.