Abstract: The zone of the communities of the grassland in the Bird island of the Qinghai Lake were selected.Total 180 plots were investigated by sampling method.Based on the plot data,the community characteristics were analyzed with species composition,flora feature,and so on.The species composition of the community was simple.There were 63 species,grouped into 43 genus and 19 families.The genus of The North Temperate was absolutely dominate.The species diversity index was different horizontaly and vertically.Plant species diversity was the lowest in the middle of height.Species diversity of plant community increased from shore to high land.In the grassland of the Bird island,there were four functional groups:grasses,legumes,nonlegumious forbs and shrubs.The correlation of the diversity,the evenness and the richness between the species level and the function level was 0.279,0.436, and 0.019.There was an apparent difference between the functional group community diversity and the species community diversity.

Key words: Polypores, Rare species, Threathened species, Changbai Mountain, Ecosystem