Abstract: Phylogenetic diversity of cultivable bacterium in the topsiol of the dolomite rocks from Yuntai Mountain was analyzed based on the culture-dependent method and 16S rRNA gene sequence analysis.One hundered and thirty-one bacterial strains were isolated by using the standard dilution-plating technique.Restriction enzyme of Hha Ⅰ and Hae Ⅲ were applied in ARDRA to analyze the 16S rRNA gene sequences,and 40 operational taxonomic units were assigned on the basis of the ARDRA patterns.The phylogenetic analysis based on the 16S rRNA genes homology showed that all isolates affiliated to 11 genera,5 phyla including Firmicutes(64.89%),β-Proterbacteria(3.82%),γ-Proterbacteria(17.56%),Actinobacteria(11.45%) and Bacteroidetes(3.82%).Bacillus(53.44%) dominated among the isolates,and followed by Stenotrophomonas(9.16%) ,Pseudomonas(8.40%) and Exiguobacterium(8.40%).Additionally,15% of strains showed similarity equal to or less than 97% in 16S rRNA sequences and may represent novel species.The results show that the diversity of cultivable bacterial species is abundant,and potential novel species exist on the dolomite from the karst area of Yuntai Mountain.