Abstract: The aim of this experiment was to perform multilocus sequence typing(MLST)analysis of Bifidobacterium longum subsp. longum isolated from adult faeces. B. longum subsp. longum were isolated from the healthy adult faeces with modified MRS media. And in order to identify and analyse polymorphism of Bifidobacterium longum subsp. longum,the experiment used physiological and biochemical experiments combined with 16S rDNA,heat-shock protein(hsp60)homology analysis and MLST. Twenty four anaerobic strains were isolated from twelve healthy adults in this study,and fourteen strains were identified as Bifidobacterium longum subsp. longum according to physical and biochemical experiments,16S rDNA and hsp60 homology analysis. The results of MLST showed that 14 strains of Bifidobacterium longum subsp. longum belonged to 10 genotypes,and they were all different genotypes from the Bifidobacterium longum subsp. longum ATCC 15707. There are larger differences in genetic polymorphism of Bifidobacterium longum subsp. longum isolated from adult faeces.