Abstract: In order to investigate the pyrolysis of vanillin in a burning cigarette, vanillin was pyrolyzed in a furnacetype pyrolyzer at 400℃, 500℃, 600℃, 700℃, and 800℃, respectively.The volatile and semi-volatile pyrolytic products were trapped by a 0.7m×0.53cm (Length×internal diameter) crystalline silica capillary immersed in liquid nitrogen, then eluted with dichloromethane, and simply qualitatively and quantitatively analyzed with GC/MS.42 pyrolytic products were identified.The formation mechanism of simple phenols, one of the pyrolytic products of vanillin, was roughly speculated according to the bonding energy of vanillin.The results showed that:1) little vanillin was pyrolyzed at 400℃, the pyrolytic products and pyrolytic rates of vanillin were increased with the increase of temperature, the pyrolytic products were significantly increased at 700℃ and 800℃, however, still there was a little of vanillin remained;and 2) of the pyrolytic products, there were key flavor compounds and there were epoxides and polycyclic aromatic hydrocarbons which molecular weights were higher than vanillin.