[Objective] The impact of vegetation restoration on the water cycle of Beichaun River basin was studied and the evolution trend of water resources in the basin under the conditions of vegetation restoration was analyzed in order to provide data support for guiding scientific vegetation restoration in arid and semi-arid areas.[Methods] The evolution trend of water cycle elements at the basin scale was analyzed based on the vegetation cover change and long-term meteorological and hydrological data at Beichuan River basin in Qinghai Province. The influence of vegetation restoration on the evolution of key water cycle elements was analyzed.[Results] Vegetation coverage in the hills and mountains of Beichuan River basin had increased rapidly since the 1980s, with an average increase of 14.98% and a maximum increase of 52.2% from 2000 to 2019. From 1956 to 2019, the annual precipitation in the basin was relatively stable, but the annual runoff showed a small decreasing trend, with an average decrease of 0.16 billion m³/10 yr. Increasing ecological water consumption caused by vegetation restoration was the main reason for decreasing runoff. Vegetation restoration had changed the spatial and temporal distribution of precipitation in the basin. In space, more precipitation was used for ecological consumption in the basin, which reduced the water supply to downstream regions. In time, more precipitation participated in the soil water-groundwater cycle, and prolonged the drainage period outside the basin. Vegetation restoration significantly reduced meteorological factors such as surface wind speed, water evaporation, and drought index.[Conclusion] Runoff in Beichuan River basin has decreased due to the influence of vegetation restoration. Additionally, ecological water consumption and the proportion of water in the cycle of precipitation-soil water-groundwater has increased, water conservation capacity has continued to increase, and semi-arid climate conditions have improved.