Abstract: Evapotranspiration(ET) is an important heft in heat balance and water balance,and its significance is obvious in estimating ET in large areas using remote sensing technology.TM images and a surface energy balance equation were used to estimate ET of the Jingning World Bank Project area on the Loess Plateau with results verified against available field data.Then relationships of ET with land use,surface parameters,terrain parameters were analyzed.Results show that daily ET value ranges from 0.70 to 9.05 mm,with an average of 5.31 mm on August 15,2003.Spatially,it displayed a rising trend from northwest to southeast,and varied with the underlying surface,being the highest with water and forest.A positive linear correlation was observed between ET and normalized difference vegetation index,but a negative one between ET and surface temperature.The findings demonstrate that the method is applicable to the estimation of ET in the study area.