Abstract: 【Objective】To understand the utilization status of Stipa breviflora steppe and guide the rational utilization of Stipa breviflora steppe.【Methods】Based on the data obtained during 2012 to 2017 from fieldworks, using sample methods at growing seasonsas , the community characteristics and classification of Stipa breviflora steppe were analyzed and summarized.【Results】The results showed that the Quantitative Characters of Stipa breviflora community had an obvious fluctuated. The species number, height, coverage, dry weight of the natural grasslands were separately 11 Species/m² ,10 cm, 27%, (100±4) g/m². The average Shannon-Wiener diversity index was 0.90, the average Margalef richness index was 2.47, and the average Pielou evenness index was 0.63. A total of 91 plants species belonged to 24 families and 58 genera were classified in Stipa breviflora steppe, among which the families with the most species were Leguminosae, Compositae and Gramineae, The species with the occurrence frequency exceeding 80% included Stipa breviflora, Convolvulus ammannii, Cleistogenes songorica, Allium tenuissimum, Stipa krylovii. As for the ecological type of water, 54 species of xerophytes and typical xerophytes accounting for 59% of the total species. In addition, perennial forbs and annul biennial specie were the two dominant life forms, covering 49% and 26% of the species respectively. Middle Asian areal-type and east Palaeo-North areal-type were the two major floristic elements, containing 42% and 21% of the species. Based on the life forms and dominances of the species within the community, Stipa breviflora steppe could be classified into 10 association groups and 15 associations,among which the constructive species was Stipa breviflora occupied 5 association groups and 10 associations.Cleistogenes songorica, Convolvulus ammannii and Artemisia frigida occupied 5 association groups and 5 associations. The latter were the degradation types of Stipa breviflora community.【Conclusion】The communities with degenerated indicator species as sub- dominant species and constructive species are widely distributed in the Northern Area of Yinshan Mountain, it means that the degradation of Stipa breviflora steppe still serious at present, need to strengthen the protection and utilize rationally of Stipa breviflora steppe.

Key words: Stipa breviflora steppe, The Northern Area of Yinshan Mountain, Community characteristics, Degradation