Abstract: To study chemical components in mainstream smoke of flue-cured tobacco from different planting areas in Sichuan Province, 35 single-grade tobacco samples (C3F) from 5 planting areas (including Liangshan, Panzhihua, Luzhou, Yibin and Guangyuan) were made into cigarettes. The mainstream smoke was qualitatively and quantitatively analyzed using a home-made smoke trapping device combined with gas chromatography-mass spectrometry (GC/MS) method, principal component analysis (PCA) and orthogonal partial least squares regression discriminant analysis (OPLS-DA). The results showed that:1) 68 chemical components were identified in the mainstream smoke of cigarette samples at matching degrees more than 79%. 2) The differences were significant among the main chemical components in mainstream smoke from southwestern Sichuan (Liangshan and Panzhihua), southern Sichuan (Luzhou and Yibin) and Northern Sichuan (Guangyuan), however, there was no detectable difference between tobacco varieties. 3) The characteristic component in tobacco from southwestern Sichuan was terpinyl acetate, and those from southern Sichuan were 2-pentanone, 1-chloroundecane, 2-acetylfuran, 2-methyl-1-phenylpropene, 5-methyl-3-hexen-2-one and styrene; that from northern Sichuan was 1-methylcyclooctene.