Abstract: The biodegradation of nitrobenzene existing extensively in the effluent wastewater of pharmaceutical factory and chemistry industries is specialized. High effective nitrobenzene-degrading microorganism is selected and acclimated under aerobic conditions, and named as Bacillus subilis. The growth conditions and the degrading characters of the strain are systematically studied. The suitable growth conditions are: pH 5.0～8.0, 30～40℃,NH\-4Cl 100～200 mg/L. The fact that nitrobenzene can be partly biodegraded into aniline under aerobic condition provides a new way of biodegradation treatment of nitrobenzene wastewater with low nitrobenzene concentration,i.e. the wastewater can be biodegraded thoroughly just by the aerobic technique,not necessary for anaerobic technique.