Abstract: This paper reports the resources and molecular phylogeny of the microbes that degrade ammonia-nitrogen pollutants in sewer.An efficient strain,JN-2,was isolated from the sludge in a large livestock farm.A screening medium was used to isolate the strain.Its biochemical characteristics and 16S rDNA gene sequence were determined to construct the phylogenetic tree.The results indicated that JN-2′s NH+4-N degrading efficiency per 24 h at 28℃ and pH 7 was 75.6% of its initial concentration of 200 mg·L-1.The accession number of its 16S rDNA gene sequence in GeneBank was JX535021.The phylogenetic tree showed that JN-2 had an 100% homology to Ochrobactrum sp..The NH+4-N reduction on sewer by the free-state JN-2 was 30.1%,and by the immobilized strain,62.8%.