In drylands, vegetation alters land surface temperature (LST) through two opposing mechanisms, which include evapotranspiration (ET) -driven cooling and albedo-induced warming. However, the dominant pathway of this biophysical feedback remains uncertain in water-limited ecosystems. Using satellite observations and the intrinsic biophysical mechanism method, we quantified vegetation-induced temperature changes across global drylands from 2001 to 2021. Results showed that vegetation increase led to a net cooling effect (Delta Ts = -0.44 +/- 0.14 K), which was overwhelmingly dominated by ET (Delta Tsf = -0.45 +/- 0.14 K), while albedo-induced warming was minimal (Delta Tsa = 0.008 +/- 0.004 K). The magnitude of ET cooling is highly sensitive to water availability, diminishing significantly when soil moisture (SM) fell below 0.15 m3/m3 and vapor pressure deficit (VPD) exceeded 1.8 kPa. Furthermore, vegetation-induced cooling intensified over time in tropical, arid, and temperate zones within global drylands, with Delta Ts declining at rates of -0.01 to -0.02 K yr- 1. While acknowledging the empirical properties of the regression and the offline assumption of the intrinsic biophysical mechanism method (which does not account for atmospheric feedbacks), our results demonstrate that ET-driven cooling dominates the biophysical cooling effect in drylands. These results provide critical insights for land-management policies aimed at reducing heat stress and ecosystem risk in drylands. Specifically, conserving vegetation in semi-arid and dry sub-humid zones may provide potential for sustained temperature regulation under appropriate management, while vegetation restoration in hyper-arid regions is unlikely to yield long-term biophysical cooling benefits due to inherent water limitations.