The invention belongs to the field of environmental treatment and particularly relates to a brachybacterium nesterenkovii-containing microbial agent. Specifically, applied brachybacterium nesterenkovii is brachybacterium nesterenkovii NY-1 with a preservation number of CGMCC No. 13747. The brachybacterium nesterenkovii-containing microbial agent is high in organochlorine degrading efficiency of upto 90-96%, short in adaptive period of dominant bacteria, and capable of rapidly starting degrading reaction within one week, and when applied to a biological reactor for purifying organochlorine-containing waste gas, can shorten the starting period.