The yield estimate equation of winter wheat considering different growth stages is established in the multiple linear regression method by means of such meteorological and ecological factors as sunlight and heat, moisture during the essential growth period of winter wheat, which are crucial to the yield formation of winter wheat in the loess plateau area of the eastern Gansu Province, as well as growth potential, a quantitative factor indicative of growing condition. It has an accuracy of over 92% in trial use. Unlike the traditional method of using single meteorological element to predict grain yields, the new method considered ecological factors and moisture, and gained satisfactory results.