This study investigated the effect of ginsenoside Rg1 on the enzyme activity of Plutella xylostella, aiming to provide reference for the study of the biological control effect of ginsenoside. The leaf membrane method was employed using ginsenoside Rg1 as the main experimental material and P. xylostella as the test insect. The dynamic effects of feeding P. xylostella with different doses of ginsenoside Rg1 on their protective enzymes [peroxidase（POD）,catalase（CAT） and superoxide dismutase（SOD）] and digestive enzyme activity were measured. The results showed that ginsenoside Rg1 had an obvious effect on the selective avoidance rate of P. xylostella at 24 h and 48 h. When the concentration of ginsenoside was 30 mg/mL, the selective avoidance rates were 92.86% and 73.51%, respectively.The inhibition of CAT and chitinase activity was the strongest under 48 h and 10 mg/mL. Under the conditions of 48h and 20 mg/mL, the inhibition of POD, AMS and lipase reached the maximum of 80%. At 24 h and 10 mg/mL, the maximum inhibition of SOD activity reached more than 90%. Ginsenoside Rg1 has significant effects on protective enzymes and digestive enzymes in diamondback moth at different concentrations, and shows inhibition and induction under certain conditions. It possesses certain biological activity and holds potential for further development.