Abstract: The calli of barnyard grass (Echinochloa crusgalli)was treated with α-terthienyl(α-T) under A-UV irrdiation for 3 h, which forms an inner environment of oxidizing stress in the cells. The results show that α-T stimulates the activity of glutathione-S-transferase(GST), glutathione peroxidase (GSH-Px) and peroxidase(POD) and inhibited the activity of superoxide dismutase (SOD) under A-UV. The activities of GST, GSH-Px ,and POD under light were higher then that non-light. The enhanced percentages of GST, GSH-Px,and POD at the concentration of (1 mg/L) under light were 26.78%, 217.66% and 124.72%,but SOD was inhibited at 1 mg/L and 10 mg/L, the inhibiting percentage was 19.95% and 55.44%, respectively. The relationship between α-T’s oxidization and anti-oxidization was discussed.