It is a very complicated problem to estimate evapotranspiration (ET) over large area of natural land surface In this paper, the evapotranspiration estimation models for dense vegetation and bare soil are presented based on information of surface parameters like vegetation fraction and surface albedo Combined with vegetation fraction data, a model for regional evapotranspiration estimation over the heterogeneous landscape is derived Meanwhile, through a case study with remote sensing data over Northwest China, the accuracy of the model for regional evapotranspiration estimation is checked, which shows a high accurate result The features of evapotranspiration over Northwest China are also discussed with the model.