Abstract: The area on both sides of the Greater Xingan Mountain is crucial region for the Filifolium sibiricum steppe. On the basis of our survey in this district the flora compositions, the ecological groups, the synusiae, the above ground biomass and spatial pattern etc. have been compared and analysed. According to the opinion of the authors, the diversity of the communities of Filifolium sibiricum steppe on both sides of the Greater Xingan Mountain reflects concretly the syngenetic characteristics of this type of steppe and it should be taken into consideration for regionalism of vegetation.