Free radicals, which are generated in several biochemical reactions in the body, have been implicated as mediators of many diseases, including cancer, atherosclerosis and heart diseases. Although the endogenous antioxidants can scavenge these free radicals, they are often insufficient to maintain the in vivo redox balance. The antioxidant activity (AOA) was examined by addition of each tested antioxidants [alpha-tocopherol (α-T), beta-tocopherol (β-T), gamma-tocopherol (γ-T), delta-tocopherol (δ-T), butylated hydroxyanisole (BHA), 2,6-di-tert-butyl-4-methylphenol (BHT), and ascorbyle palmitate (AP)] to four types of different vegetable oils (sunflower oil, soybean oil, corn oil and olive oil). Moreover, content changes in fatty acids were then investigated every 3 months during the storage period. The results showed that the AOA was different among the tested antioxidants. The AOA for BHA was the most for different types of oil compared with other antioxidants, whereas the δ-T possessed the lowest AOA.