Abstract: Potential evapotranspiration (ET₀ ) is a critical element that impacts the water cycle of a river basin. Understanding the characteristics of future changes in ET₀ and the quantitative impact of its driving factors is of great significance for coping with the variation of water cycle under future climate changes. Using the Peman-Monteith formula and ensemble data from five climate models, we estimated the temporal and spatial trends of China’s potential evapotranspiration from 2030 to 2060, and applied partial differential methods to quantify the contributions of various factors driving ET₀ changes. The findings reveal that under the RCP4.5 and RCP8.5 scenarios, the ET₀ of five major climate zones in China will exhibit an increasing trend in the future, with rates of increase reaching 1.32 mm/a and 1.96 mm/a, respectively. The fastest growth rate of ET₀ is observed in the subtropical climate zone, while in the plateau mountain climate zone, the growth rate is the smallest. The growth rate of ET₀ in the five climate zones under the RCP8.5 scenario is greater than that under the RCP4.5 scenario. Overall, ET₀ exhibits an increasing trend in all four seasons of the year. Under the RCP4.5 scenario, the ET₀ growth rate is the greatest in autumn (0.56 mm/a), while under the RCP8.5 scenario, the largest growth rate is observed in summer (0.63 mm/a). Future changes in ET₀ are primarily affected by daily maximum and minimum temperatures, as well as actual water vapor pressure. Daily maximum temperature is the dominant meteorological element governing the magnitude of ET₀ changes, followed by actual water vapor pressure. Similar patterns were found in the analysis of the driving factors of ET₀ changes in all four seasons. The research findiugs provide reference for optimal allocation of water resources and agricultural irragation management in future.

Key words: potential evapotranspiration, climatic regions, Peman-Monteith formula, change characteristics, driving factors