The purpose of this study was to investigate the antioxidant effect of aqueous green tea(AGT) on soybean oil. AGT was freeze-dried and 20% of the freeze-dried aqueous green tea powder (AGTP) was added to soybean oil in the quantities of 0.5%, 1% and 5%. Soybean oil without the addition of AGTP was used as a control. Soybean oil with 0.02% butylated hydroxytoluen(BHT) was used as another experimental sample. Each sample was stored at 6$0^{circ}C$ for 15 days. The oxidation of these samples was determined by measuring the acid value (AV), peroxide value (POV), and thiobarbituric acid (TBA) value. The result showed that the acid values were lowest in 0.02% BHT, followed by the 0.5% AGTP, 1% AGTP, 5% AGTP and finally the control. When AGTP was added, the peroxide value was lower than both the control and 0.02% BHT. The lowest TBA values were in the 0.5% AGTP followed by 0.02% BHT, 1% AGTP, 5% AGTP and the control, respectively. The 5% AGTP (285 min), 1% AGTP (249 min) and 0.5% AGTP (238) demonstrated longer induction periods, compared to the control (204 min) and the BHT (229 min) by Rancimat method.