Abstract:The purpose of this article was to analyze the impacts of afforestation in different regions and seasons on the Loess Plateau on the land surface temperature (LST) from 2002 to 2015 and their driving factors (Albedo and evapotranspiration) based on MODIS land cover, LST, Albedo, evapotranspiration (ET) data products and precipitation data. The results showed that during the study period, the cooling effect in the daytime dominated LST change ((-0.78±1.25)℃) and the cooling effect was mainly driven by ET ((0.84±1.35) mm/d). Moreover, the land surface temperature change caused by afforestation was closely related to precipitation, and afforestation would cause a slight warming ((0.03±0.22)℃) in semi-arid regions where the mean annual precipitation was less than 400 mm. In addition, the variations of LST presented a seasonal pattern, that was, the observed cooling effect in spring and summer was greater, while in winter, this effect was weak. The daytime cooling effect was the strongest in spring, followed by summer, winter and autumn. In terms of the nighttime LST, the warming effect in winter was the strongest, followed by spring, autumn and summer. Meanwhile, the correlation between LST variations and ET change(Albedo change) showed that the cooling effect derived by ET offset the warming effect caused by albedo and dominated the daytime LST variations. Such warming impact at night reflected that storage heat during the day was likely to be released at night. Vegetation restoration on the Loess Plateau had a cooling effect, which slowed down the trend of climate warming on a regional scale.