A SWAT model with added reservoir and water intake modules was constructed. On the basis of considering the impact of human activities, the impact of land use types and climate change on hydrological elements in the Ziya River Basin was analyzed. And the integrated reduction method was used to calculate the contribution rate of human activities and climate change to the runoff changes in the study area. The results show that from 1980 to 2020, the area of grassland, arable land, and water showed a decreasing trend, while the area of construction land showed an increasing trend. The change trend of other land use types was not significant. The change in land use type has led to an increase of 3.5mm in surface runoff in the basin, and a decrease of 0.15mm and 2.93mm in groundwater recharge and evaporation, respectively. From 1980 to 2020, the annual precipitation in the research area showed an insignificant upward trend, while the annual temperature showed a significant upward trend. Climate change has led to varying degrees of increase in surface runoff, groundwater recharge, and evapotranspiration in the basin. The contribution rates of human activities and climate change to the reduction of watershed runoff are 66.36% and 33.64%, respectively, with human activities occupying a relatively dominant position.