Abstract: Based on MODIS-MOD16A3, ERA5-Land reanalysis data, and Digital Elevation Model (DEM) datasets, with Sen's slope estimation, coefficient of variation method, Ridge regression model, and Hurst index, the spatiotemporal variations of evapotranspiration (ET) in Southwest China from 2014 to 2023 were analyzed, and the primary driving factors and future trends of ET changes were explored. The results reveal that: (1) Over the past decade, ET in Southwest China exhibited relatively stable fluctuations with no significant overall trend. Most regions showed an increasing trend, with the rate of increase from high to low in the order of Sichuan, Yunnan, Chongqing, and Guizhou. The most pronounced upward trend was observed in the Sichuan Basin, while a significant downward trend was only found in the western part of the Western Sichuan Plateau. (2) The main factors influencing ET changes, in descending order of importance, were 2 m air temperature, total precipitation, surface solar radiation, soil moisture content, and leaf area index. Among these, 2 m air temperature contributed the most, accounting for 42.86%. (3) DEM showed a positive correlation with ET, while the correlations between ET and other meteorological factors exhibited significant spatial heterogeneity. (4) Based on the Hurst index estimation, it is projected that ET in Southwest China will continue to show an increasing trend in the future.