This study assessed the antioxidant activity and residue level of phenolic antioxidants in autoxidation of linoleic acid. The antioxidant activity of phenolic antioxidants was measured based on peroxide value of linoleic acid at 50°C for 8 days. We further evaluated the residue level of phenolic antioxidants in the autoxidation period by HPLC-UV. The residue level of antioxidants changed with time starting on day 0 (100%) and was determined by 100-remaining of antioxidants (%). Our results showed that peroxide values ranged from 0.33 to 10.18 meq/kg in propyl gallate, from 0.67 to 11.01 meq/kg in dodecyl gallate, from 0.01 to 10.34 meq/kg in octyl gallate, from 0.01 to 4.17 meq/kg in butylated hydroxytoluene (BHT), from 1.00 to 5.85 meq/kg in butylated hydroxyanisole (BHA), from 0.33 to 4.18 meq/kg in 2,4,5-trihydroxybutyrophenone, and from 1.00 to 11.01 meq/kg in tert-butylhydroquinone (TBHQ). Among the residue levels of antioxidants, on day 8, BHT showed the highest level while TBHQ showed the lowest. BHT showed the highest correlation coefficient, whereas BHA showed the lowest. This study proves that the residual level of phenolic antioxidants has a good correlation with the degree of autoxidation in linoleic acid.