Abstract: This is a new way estimating large area evapotranspiration by thermal infrared satellite remote sensing data. On the basis of energe balance equation, local evapotranspiration was calculated by the difference of plant canopy and air temperature that was presented by field measuring ground surface thermal infrared tempreture and a varity of meteorological factors. Furthermore, large area evapotranspiration and distribution were estimated by thermal infrered satellite data. Study results of the way are more similar to value of field measurement, which was verified. The way will be inproved in order that it will be real applicated.