A gas chromatographic method has been developed for monitoring trace amount of volatile organics in deep-treated waste water from a duprene plant to examine the efficiency of the treatment.A gas stripping technique was used to concentrate the organics in order to increase the overall sensitivity.The detecstion limits for chloroprene,diving lacetylene and benzene are all 0.004 mg/l.and for acetaldehyde,0.006 mg/l.The dynamic process of activated coal used in the treatment of the waste water was also illustrated.This method is probably applicable to the determination of other volatile organio substances in water at ppb level.