The sublethal effect of insecticides and SlNPV on the activities of superoxide (SOD),catalase (CAT) and peroxidase (POD) in Spodoptera litura was investigated under 28℃. The results showed that the SOD activity in the treatment of chlorpyrifos and SlNPV mixture was significantly higher than those in the treatments of chlorpyrifos, SlNPV and the water control. It was 1.18, 1.35 and 1.25 times that of the water control at 12, 24 and 36 h, respectively. The SOD activity in the treatment of chlorfenapyr and SlNPV mixture was lower than those in the treatments of chlorfenapyr, SlNPV and the water control after 12 h. The CAT activity in the treatment of chlorpyrifos and SlNPV mixture was significantly higher than those in the treatments of  chlorpyrifos, SlNPV and the water control. It was 2.79, 1.09 and 1.53 times that of the water control at 12, 24 and 36 h, respectively. The CAT activity in the treatment of chlorfenapyr and SlNPV mixture was lower than those of the water control except at 12 h. POD activity could not be investigated in S. litura. It was obvious that there was a great difference in the activity of CAT mostly after treatment of the mixture of insecticides and SlNPV.