Accurate evapotranspiration (ET) estimation is vital for the ecology and water resource management of arid and semiarid regions. This study focused on the Kolqin Sandy Land Inland Closed Basin. The simulation of energy flux data for the area was conducted by applying Landsat 8 data from 2018 to 2022 during the growing season, the Two-Source Energy Balance (TSEB), and the Mapping Evapotranspiration at High Resolution with Internalized Calibration (METRIC) models. The validation of both models was performed via eddy covariance systems and large-aperture scintillometers, and the applicability of both models was compared. At the ecosystem scale, the TSEB model exhibited excellent accuracy of latent heat flux simulation in dune and meadow ecosystems (R²>0.8, RMSE<45.74 W/m², and MAPE<26%), while the METRIC model excelled in meadow ecosystems (R² = 0.89, RMSE = 27.79 W/m², and MAPE = 12%). In contrast, at the regional scale, the TSEB model outperformed METRIC for sensible heat flux simulation (R²: 0.65-0.68, RMSE: 22.83-43.28 W/m², MAPE: 14%-17%). The TSEB model ranked evapotranspiration in the order of lakes>meadow wetlands>farmland>dunes, peaking in August and following a seasonal pattern of summer>spring>autumn. Additionally, evapotranspiration varied with LAI during the pre-middle growth period and responded significantly to △T in the late vegetation period.