In order to assess the red upland soil fertility under longterm different fertilization patterns,5 indexes,including the soil pH,organic matter content,available phosphorus content,available potassium content and cation exchange capacity were selected to assess and compare the comprehensive soil fertility under different fertilization patterns after 30 years by fuzzy mathematics and principal component analysis in doublemaize cropping system from 1986 in red upland soil.The results showed that the KMO of data sphericity test was 0.73,and the bartlett was 127.98,the principal component analysis could be carried out with these data.The soil nutrient index(SNI)of application of chemical fertilizer combined with pig manure was the highest(094),followed by single application of pig manure(0.92),and the single application of nitrogen fertilizer(0.42)was the lowest.Therefore,the application of organic manure or organic manure combined chemical fertilizer is wise measure to maintain and improve soil fertility in red dryland soil.