[Objective] The annual runoff changes and leading factors in Qingshuihe River basin and Baihe River basin were comprehensively analyzed, and the actual runoff changes and influencing factors in the two river basins were further revealed, in order to provide theoretical basis for water resources planning and management in Zhangjiakou region. [Methods] Based on Budyko model, the study was conducted for the Qingshui River basin in the upper reaches of the Yongding River and the Baihe River basin in the upper reaches of the Chaobai River. Coupled water-heat balance equations for the basins were constructed. Sensitivity coefficients of potential evapotranspiration to major meteorological factors were accurately calculated, and then elasticity coefficients of runoff to major meteorological factors from the sensitivity coefficients were calculated. Finally, the contributions of climate change and human activities to runoff changes were calculated. [Results] ① The elasticity coefficients of meteorological factors in the Qingshui River basin and the Baihe River basin showed increasing trends in recent years, indicating that the increasing climate-hydrology coupling in these two basins and the hydrological processes in the Qingshui River basin were more sensitive to climate change than the coupling and processes in the Baihe River basin. ② Human activities dominated changes in the runoff of the Qingshui River basin and the Baihe River basin. The contribution rates of human activities to runoff changes in the Qingshui River basin and the Baihe River basin were 65.37% and 83.90%, respectively. ③ Compared with the Fu, Choudhury-Yang, and Wang-Tang formulas, the Zhang formula had better applicability in Qingshui River basin and the Baihe River basin. Actual evapotranspiration from the basins was modeled better, with the R² value reaching 0.97. [Conclusion] The contribution of human activities to runoff changes in the study area ranged from 65.37% to 83.90%, and the contribution of climatic factors ranged from 16.10% to 34.63%. In the future, the impact of climate and human activities should be considered at the same time. Continued efforts should be made to strengthen research on the mechanisms and processes of runoff and evapotranspiration in water limited environments, therefore to ensure the security of water resources.