Based on the systemic introducing of concepts about ecostratigraphy, dmmb Community Zone and community formation are put forth first time in this paper and are taken as systemic ecostratigraphy classificstion unit together with subcommunity Zone, community Zone and Community group. By the study of triassic of Hongxin area of West Qinlin, seven community zones.one dumb community zone, two community Formations and one community group have been established. Community evolution of early-middle triassic of Hongxin area has been studied finally in this paper.