Instantaneous evapotranspiration in Huangfuchuan watershed is retrieved based on the estimation of land surface characteristic parameters and fluxes using Landsat5 tM. Daily evapotranspiration is found by scaling. Water body is dealtwith as bare land. The characteristics between water body and soil are very dis-tinct,so Penman model is used to calculate water evaporation and the calculated resultis merged into daily evapotranspiration. Results show thatdaily evapotranspiration retrieved is accord with the status of land sur-face. The relative error of surface temperature retrieved is 0. 58% and the relative error of daily evapotransp-i ration retrieved is 11. 75%,which are both permitted.