According to the predator prey relationship,the total community of arthropod could be divided into two sub-communities:sub-community of natural enemy and nonnatural enemy.On the basis of investigation of groups,individual numbers and analysis of some other ecological indexes,the arthropods investigated in this garden belonged to 55 species of 47 families,nonnatural enemy sub-community was dominant in the total community,the relative abundance was 0.8948 and that of natural enemy sub-community was 0.1055.The analysis of dominant concentration and diversity indexes showed the following orders:sub-community of nonnatural enemy>total community>sub-community of natural enemy and sub-community of natural enemy>total community>sub-community of nonnatural enemy.