Abstract: Based on the method of toxicology, mice were administered with different dosage olaquindox by intragastric administration in order to investigate the effect of olaquindox on function of serum antioxidation in mice. The results were as follows. Olaquindox had a significant effect on the function of organism antioxidation. Low doses of olqquindox can increase the serum T-AOC in mice, and the high doses can produce a certain Inhibition. Olaquindox with high dose made the activity SOD and GSH-Px of antioxidase system rise, content of MDA and T-AOC lower, suggesting that olaquindox caused the decrease of antioxidation capacity by the regulation of other than GSH-Px and SOD. These antioxidation factors might not only eliminate the activity effect of GSH-Px and SOD, but also reduced significantly the body's antioxidant levels.