Land evapotranspiration (ET) is essential for the hydrological cycle and surface energy balance. Investigating the spatiotemporal evolution and response to land cover changes is of significance in socioeconomic development and regional water resource management. However, consistent estimation of ET is challenging due to “space-time” conflicts in optical remote sensing data and susceptibility to cloud contamination. This study adopted the GF-SG model for reconstructing high-resolution NDVI time-series data from the Yellow River Basin of Inner Mongolia. These data were then input into the Priestly-Taylor Jet Propulsion Laboratory (PT-JPL) model for improving the resolution of ET retrieval. ET was estimated at an 8-day 30m resolution from 2000 to 2022, and its spatiotemporal patterns were analyzed. The model sensitivity parameters were optimized and validated based on in-situ observations from the eddy covariance stations. The optimized PT-JPL model demonstrated excellent simulation results in the basin, with calibration period accuracy ranging from the R2 of 0.88 to 0.91, RMSE between 0.57 and 0.60 mm/d, and MAE from 0.38 to 0.46 mm/d. The validation period accuracy ranged from the R2 of 0.85 to 0.87, RMSE between 0.54 and 0.72 mm/d, MAE from 0.36 to 0.47 mm/d. Over the past 23 years, the mean basin-wide ET has been 304.18 mm, with an increasing trend of 2.587 mm/ year. Spatially, ET exhibited west-low and east-high distributions. Across the basin, most (82%) of the trends in ET change were not significant, with noticeable increases mainly in the eastern regions, such as the Daheihe and Hunhe River Basins. Future ET trends mainly showed increasing or non-continuing patterns. The sequence of ET increase in various land use transfer areas was transfer to forest land > transfer to cropland > transfer to construction land > transfer to grassland > transfer to unused land.