Abstract: East Juyanhai as one of the major lakes in Inner Mongolia Plateau, the survival status of microorganisms in water is not clear.In this study,74 bacterias was isolated from lake water samples. According to the 16S rDNA sequences system phylogenetic analysis showed that, Alphaproteobacteria strains up to a total of 39 Accounts for about 53% of the total bacteria; Actinomycetes （Actinobacteria） is the second dominant groups,a total of 19 strains,representing 26% of all strains.ln addition, the nine isolated from Bacillus groups,six from γ-proteobacteria groups and one from the β-proteobacteria （Betaproteobacteria） groups. These bacteria belonging to 23 genera, which Caulobacterales of Brevundimonas dominant population, a total of nine.