The crop growth models have the functions of reflecting the interaction of crops and climatic environment, describing the growing process of crops, and quantifying the relationship between crop growth and environmental factors. In this paper, the suitability of crop growth model WOFOST was analyzed and tested in regional scale based on experimental data. Localized model WOFOST was used to quantify and dynamically evaluate the drought disaster of winter wheat in North China. Applying the standard of yield reduction rate and calamity degree and numerical simulation experiments, the study determined the main meteorological factor which leads to yield reduction and conducted drought index of winter wheat. Based on the drought index, drought disaster at typical years and decadal drought disaster were evaluated.