Abstract: The tobacco samples were prepared with simultaneous distillation and extraction and quinoline was used as an internal standard (IS). The aroma components in the samples were analyzed by GC/MS with selective ion mode. The analytical conditions were as follows:the column was a capillary column, HP INNOWAX (30m×0.25mm i.d.×0.25μm d.f.); the carrier gas was helium, constant pressure 75kPa; the injection temperature was 250℃, injection mode was splitless, and injection volume was 1.0μL. Temperature program was that the initial temperature was 60℃, rose to 180℃ at 2.5℃/min., kept for 10 minutes, and then increased to 250℃ at 5℃/min., kept for 3、minutes. Temperatures of transfer line and ionization source were 220℃ and 200℃, respectively. Ionization energy was 70eV. Scanning mode was selective ion and the scanning range of ion mass was from 33 to 350 amu. 34 aroma constituents were quantified, of which the RSDs (on the basis of the ratio of peak area of aroma constitute to the same of the IS) of 30 aroma compositions were less than 5% and those of 4 components were from 5% to 8%. That indicated that the repeatability of the method was good. The contents of the 34 aroma constitutes in 4 commercial cigarettes were also analyzed and compared.