This study was to evaluate the effect of leaf temperature on daily evapotranspiration of crop. A transpiring crop will be cooled by the vaporization of water to a temperature below that of the surrounding air. Leaf temperature was measured a infrared thermometer. Crop evapotranspiration was measured by the method of lysimeter. A statistical model for estimating evapotranspiration was developed and tested. It was showed that the model was applicable.