Antioxidative activities of fresh, steamed and black garlics by different processing condition were investigated on the soybean oil. The crushed fresh, steamed and black garlics were added to 100 mL of soybean oil at a level of 0, 5, 10, 20 and 40 g respectively, and then the oil mixture containing garlics (reaction samples) were heattreated for 48 hrs at 180℃ . The chromaticity of reaction samples were increased during heating. After 48 hrs heating, in the sample added 40 g/100 mL chromaticity of each samples were 1.36, 2.99 and 1.99, in the crushed fresh, steamed and black garlics, respectively. Anisidin value showed irregularly increased during heating. Acid values of reaction samples were higher than control during heating, those levels were ranged from 0.82 to 2.04 mg/g after 12 hrs, were gradually increased to 3.15~4.30 mg/g after 48 hrs. Peroxide value of reaction sample containing black garlic(40 g/100 mL) was lower than the samples containing tocopherol or BHT, after 48 hrs heating. TBA value of reaction samples containing fresh, steamed and black garlic of 40 g/100 mL were the lowest in the sample added black garlic, after 48 hrs heating. These results suggested that oxidative stability of black garlic in soybean oil was more potential than the other garlics during heating.