The total arthropod community was divided into two sub-communities: natural enemy and non-natural enemy by the standard of nutrition and hunting, based on systematic investigation of arthropod community structure of soil and water conservation-type tall fescue. On the basis of investigation of groups, individual numbers and some other ecological indexes, the structure of total community and sub-community was analyzed. The result showed that the arthropod investigated belonged to 139 species of 68 families, non-natural enemy sub-community was dominant in the total community, the relative abundance was 0.7661, the dominant species were Homoptera insects, and that of natural enemy sub-community was 0.2339, the dominant species were natural enemy of spiders. The analysis of dominant concentration and diversity indexes showed the following orders: sub-community of non-natural enemy>total community>sub-community of natural enemy, and the analysis of evenness showed the following orders: sub-community of natural enemy> total community> sub-community of non-natural enemy except May and Sept., the analysis of diversity showed the following orders：total community> sub-community of natural enemy> sub-community of non-natural enemy>total community except April and May.