With the soil element content distribution in Zhangye-Yongchang region as the main basis and on the basis of analyzing the soil pollution situation and the status of the beneficial elements in the survey region, the authors selected six kinds of soil quality evaluation indices, such as necessary major elements, necessary trace elements, beneficial elements and harmful heavy metal elements, and, according to the weight threshold calculated results of various indices and the membership function calculation model, divided the soil quality of the survey region into five grades, i.e., high-quality, superior, fine, moderate and bad, which possess 4.88%, 47.21%, 29.08%, 14.49% and 4.34% of the total area of the survey region respectively.