Abstract: To improve the efficiency of anaerobic,low-temperature bioconversion of waste materials to methane, 3 groups of psychrophilic microflora were studied. Dried cow manure was collected from local cattle farms for an enrichment culture at 15℃.From the culture,Group #5 microflora was identified as a potential source for further investigation. The microbes of the group were inoculated in the waste water effluent from a pig farm to obtaine the low-temperature resistant Group Y5S. The microbial communities of Y5S,#5, and YJ (a microflora group originated from pig farm sewer)were compared. In all 3 groups, microbes belong to the phylums of Firmicutes, Bacteroidetes, Synergistetes, Proteobacteria, Spirochaetes, and Verrucomicrobia were found.They shared 85 core microbiomes of Clostridia class in Firmicutes phylum,as indicated by the high-throughput sequencing.At genus level,these psychrophiles included Acetobacterium, Citrobacter, Clostridium, Desulfobulbus, Desulfomicrobium,Hydrogenophaga, Oscillospira, Parabacteroides, Ruminococcus, Sedimentibacter, Sphingomonas, Sulfurospirillum, Syntrophomonas, Trichococcus,and Devosia. Synergistetes in the mocroflora of Y5S seemed to suggest that this kind of microorganism might play an important role in the biogas fermentation.