Abstract: According to the variation law of rice evapotranspiration,a linear regression method and a three-times smoothing method with exponential weight cocfficicnts are proposed for forecasting the rice evapotranspiration of different growing seasons respectively in this paper.The analysis of three real-world caamples shows that the two methods work well.Meanwhile; the proposed methods might be useful for forecasting the evapotranspiration of other crops.