Abstract: In order to study effects of reaction conditions on oxidation of β -carotene, different degradation products were analyzed by GC -MS. Results showed that oxidative degradation products of β-carotene included 2, 2, 6 -trimethyl -cyclohexanone, isophorone, β-cyclocitral, β-ionone, dihydroactinidiolide, and so on. The content of dihydroactinidiolide was much higher than that of other components. Solvents, pH and reaction time had effects on composition of degradation products of β-carotene in different degree. Compared with diethyl ether, petroleum ether and cyclohexane, ethanol system was better for oxidative degradation. In addition, with the pH declined or reaction time expanded, total amount of main flavor components reduced before increasing. The optimum degradation conditions determined by this method were holding for 3h at pH3.0 in the medium of ethanol.