Abstract: The key technology of deep-litter system is the activity of microbial communities， so superior bacterium of deep-litter system become research hotpot in recent years. To provide a scientific basis for the deep-litter system， efficient bacteria strains were isolated by using pure culturing methods and the microbial community diversity were studied. The dominant bacteria in the active deep-litter ecosystem for pigs were studied and 10 strains were isolated.All of them were identified to be different specie， including 5 Bacillus strains by morphology analysis， 16S rDNA sequence analysis and homology analysis.The isolated Bacillus strains were resistant to heat and some were good for the deodorization by decomposing manure with related enzymes. Furthermore，some pathogenetic bacteria were inhibited by the filtered extracellular cultures of the isolated stains. This research indicated that Bacillus sp plays an important role in the deep-litter systems to achieve the goals: safty， enviroment protection.

Key words: deep-litter system, Bacillus strain, enzyme activity, pathogens inhibition activity