The main economic characters of 45 walnut species from Jianshi County, Hubei, which include fruit weight, per fruit weight, per kernel weight, kernel rate, index of kernel catching, kernel weight, content of crude lipids, content of crude proteins, and content of soluble sugars, were analysed by principal component analysiss according to the correlation matrix of samples. According to more than 91% of the cumulativee variance proportion, six principal components and their function equations of the main economic characters of walnut from Jianshi, Hubei, were proposed. The relevant combinations of the principal components were proposed according to the trendency of market requirement after the important values of the principal components were computed, and the synthetical evaluating indexes were built according to the arrangement of the excellent trees for different market aims. The results are similar to the actual phenotypes of excellent trees, suggesting synthetical index analysis is more scientific and simple than the tranditional giving marks and single charactered selection in evaluation of the main economic characters of walnut. The results provided theoretical basis for the selection and usage of walnut.
