Abstract: In order to attain the higher yield of allin and higher content of that in garlic oil, the key effect factors were investigated: as the reaction time was prolonged, the yield of allicin was increased, but the byproduct of reaction was presented after more than four hours.As the reaction temperature and reactant concentration and the ozone flow increased, the yield of allicin was first increasing and then decreasing.The respond surface methodology was used to optimize the synthesis condition of the reaction: the reaction time was 4h, and the reaction temperature was about 8.06℃, and the ozone flow was 0.28L /min, and reactant concentration was 0.18mmol /mL. In the above optimized synthesized condition, the ozone was used to oxidize the garlic oil, the yield of allicin was 59.53%. The garlic oil with high content of allicin could be obtained and the quality of garlic oil could be improved in the above-mentioned optimized condition.