Abstract: The evapotranspiration estimation model is presented based on energy balance through remote sensing.The parameters of the model could be modeled using empirical and semi-empirical formulas;Based on net radiation convert coeffcient and Bowen ratio,combining theory of Sequin and Itier derive the daily evapotranspitation experience model of calculation;in respect that the temperature can influence the instantaneous evapotranspiration,which improve the estimation accuracy of the daily average evapotranspiration.As in different area,adjusting net radiation convert coefficient only can solve the daily evapo-transpiration calculation problem from the instantaneous evapotranspiration value.Through a case study in Heilongjiang Province,it proves that this model has strong practicality and can offers scientific basis for the operation of drought monitoring system.