Abstract: In order to develop a new tobacco flavor, a method of producing aromatic substance via enzyme catalysis of β-carotene was established. The conditions of oxidative degradation of β-carotene catalyzed by xanthine oxidase were studied, and the effects of reaction phases, enzyme amounts and organic solvents on the yield of aromatic substance were investigated. The results showed that: 1)The degradation products included isophorone, β-cyclocitral, β-ionone and dihydroactinidiolide, which were major aromatic substance in tobacco and tobacco products. 2) Comparing with the system of organic or water phase, the biphase system of oil-in-water was more beneficial to the formation of aromatic substance. 3)The yield of aromatic substance in the product increased at first and then decreased with the increase of xanthine oxidase. 4)Appropriate addition of low polar solvents to the oil-in-water system would improve the catalytic activity of xanthine oxidase and inhibit further degradation of intermediates.