By taking the North China Plain as the study region, the winter wheat and the summer maize are selected as the typical crops for calculating the net irrigation water demand with the crop coefficient approach on the basis of the pre-estimated climate scenario,and then the water demand process and the total water demand of both the winter wheat and the summer maize under different temperatures and precipitation changing amplitudes are analyzed. Meanwhile, the drought-prone areas are regionalized in accordance with the abnormal degrees of the meteorological drought and the water demand. The study result can provide reference for the researchers concerned.