In order to forecast the effect of climate warming on agriculture, ENWATBAL model was used to simulate evapotranspiration of winter wheat due to the change of air temperature and precipitation in the coming decades. The effect of climate warming on winter wheat yield in the future decades was speculated by the past yield and climate data in last decades, and the possible water use efficiency in the future decades was calculated. The results indicate that climate warming would increase winter wheat evapotranspiration, and decrease yield and water use efficiency of winter wheat. It shows that climate warming would intensify the water shortage in agriculture, and it is necessary to develop water-saving agriculture.