Simulation and prediction of runoff under climate change and land use scenarios are of great significance for the study of water balance and water resources planning and management. Taking the Qingshui River Basin in Zhangjiakou City as the research area, the global climate model GFDL-ESM2M and CA-Markov model were used to analyze and predict the meteorological data and land use in the Qingshui River basin, and the SWAT hydrological model was constructed to quantify the changes of water balance factors in the basin in 2025 under the joint influence of climate change and land use. The results show that under the three GHG emission scenarios, the rainfall in Qingshui River Basin increased significantly in 2025, the maximum temperature and average temperature under the RCP2.6 emission scenario decreased compared with 2015; The maximum temperature and average temperature under the RCP4.5 and RCP8.5 emission scenario increased, and the minimum temperature under the three scenarios decreased. From 2015 to 2025, arable land, woodland, grassland, water area and construction land changed by -6.24 %, -0.86%, 6.32%, 0.20% and 0.59%, respectively. Compared with 2014-2015, the water balance distribution of the watershed changed in 2025, and the peak monthly runoff occurred from July to September. The average annual runoff under the three discharge scenarios were 4.40 m³/s, 5.84 m³/s and 9.94 m³/s, respectively.