The tendency corn yield term (Yt) and climatic corn yield term (Yw) of Gansu province are expanded by means of EOF. Their first characteristic vectors show that general tendency is consistent with the tendency yields of Gansu. The centers of large values is the large variabilities. By means of correlation analysis between Yt time coefficients and Yt for station, and the same method to Yw, eight stations for predicting corn yield are chosen, which represent basically yield levels and growing conditions under various kinds of agroclimatic regions of Gansu Province.