A strain of aerobic denitrifier N1 screened from the biofilm of BAF combined reactor for treating high concentration organic pharmaceutical wastewater was found capable of aerobic denitrification, which can be used nitrate of potash by as sole nitro-gen source. The results indicated that the strain N1 was most similar to Pseudomonas monteilii based on the results of morphologic characteristics, physiological and biochemical properties and phylogentic analysis of 16S rDNA sequence, and the sequence had the highest similarity of 99.2% with 16S rDAN sequence of strain Pseudomonas monteilii strain CIP 104883 obtained from GenBank using BLAST. At present, there are few reports on the degradation of nitrate nitrogen with Pseudomonas monteilii. The nucleotide sequences of strain N1 have been submitted to the GenBank databases under accession numbers HQ840771. So far there are few studies related to aerobic denitrificaton of Pseudomonas monteilii. Therefore, the study is high valuable for treating nitrogenous wastewater using microbe technology.