Abstract: The biodegradation of aniline by the obligate aerobic bacteria,named as Ochrobactrum anthropi,has been studied.The initial concentration of aniline and inoculate quantity affect the rate of biodegradation.When the initial concentration is below 800 mg/L,the rate will increase with the increase of the concentration.When the initial concentratyion is higher than 1000mg/L,the degradation will be inhibited.The obligate bacteria can degrade aniline completely in certain range of concentration.The reaction of biodegradation assumes zero or one order in different range of concentration of aniline,according to the analysis and calculation of the kinetic of degradation process.