Abstract: A gas chromatographymass spectrometric method which can quickly detect 15 volatile organic compounds in water samples is established through the optimization of chormatograhic conditions and the improvement on selected ion monitoring mode. The method uses the temperature programming (gas) chromatography which remarkeably shortens the running time of chromatography (within 17 minutes). It also uses the segment selected ion monitoring mode which increases sensitivity and gets lower detection limits. The detection limits of the method for 15 volatile organic compounds are less than 1.0 ng/L and the higher recovery of 78％~103％ is obtained.