Abstract: The development of the remote sensing technology provided a new method to estimate land surface evapotranspiration for the large areas.The theories of several methods of regional evapotranspiration,such as land surface energy balance and complementary relationship of land surface evapotranspiration were analyzed firstly.Based on the introduction of models and algorithms,the main merits and shortcomings about these models and algorithms were then discussed.Finally,the problems faced in the research of the land surface evapotranspiration based on the remote sensing technology and its future development trends were analyzed.

Key words: Remote sensing, Remote sensing, Energy balance, Land surface evapotranspiration, Uncertainly