In order to find out the antioxidant protection effect of synthetic antioxidants ethoxyquin (EQ) and butylated hydroxytoluene (BHT) on the concentrate, six antioxidant groups and one control group were formed by adding different kinds and contents of antioxidants into 25% concentrate (the amount of antioxidant added was zero). The antioxidant groups were E1 (150 mg·kg-1 EQ), E2 (300 mg·kg-1 EQ), E3 (450 mg·kg-1 EQ), B1 (91 mg·kg-1 BHT), B2 (182 mg·kg-1 BTH), B3 (273 mg·kg-1 BHT). Samples were taken every seven days in a constant temperature and humidity incubator, and the acid value (AV), peroxide value (POV) and malondialdehyde (MDA) of the extracted oils were determined according to the national standard method. Each group has three replicates, and the test period was 90 days. The results showed that POV value of each group with 60% EQ was lower than that of each group with BHT at the corresponding dose in the first to tenth week. During the 3rd∼9th week, POV values of B1 group were significantly higher than those of other treatment groups (P<0.01); however, POV value of E2 and E3 groups were significantly lower than that of other groups from the 3rd to 12th week (P<0.01). During the whole test period, MDA content of each group showed a decreasing trend with the increase of antioxidant addition, the MDA content of E2 and E3 groups were significantly lower than that of the other groups from the 6th to 12th week (P<0.01). It was found that as the amount of antioxidant increased as the protective effect of the oil in the concentrate was better; the protective effect of EQ antioxidant in equal concentration was better than that of BHT antioxidant; the protective effect of 60% EQ antioxidant added with 150 mg·kg-1 was better than that of the three times the dose of BHT.