Investigations on structure of arthropod community in peach gardon were conducted with the principal component analysis, the optimal sorting method and fuzzy clustering analysis. The results showed that more obvious main factors and temporal patterns exist in the community. Dealing with the population dynamics of 55 species of arthropods by fuzzy clustering analysis and taking lambda = 0.47, we divided the community into four stages. The number of pests and their natural enemies was divided into three parts by the optimal sorting method. The dominant species of pests and their natural enemies were demonstrated by the principal component analysis.