Effects of beta-cypermethrin, abamectin, chlorpyrifos, thiamethoxam and bisultap on toxicity against 1st-6th instar larvae in Phauda flammans Walker (Lepidoptera: Zygaenidae) were tested using the leaf-dipping method. Meanwhile, effects of these pesticides on detoxifying and protective enzymes in P. flammans larvae were also measured. Results showed that the LC50 value of beta-cypermethrin, abamectin, chlorpyrifos, thiamethoxam and bisultap against P. flammans larvae were related to the instar and pesticide. Control efficacy of beta-cypermethrin was the best among of these pesticides, and the LC50 value of which against 1st instar larvae in P. flammans reached 2.038 mg/L at 8 h after treatment, and reached 6.416-48.764 mg/L for 2nd-6th instar larvae at 24 h after treatment. Control efficacy of abamectin was less than beta-cypermethrin, and the LC50 value of which against 1st instar larvae in P. flammans reached 241.953 mg/L at 8 h after treatment, and reached 19.285-266.207 mg/L for 2nd-6th instar larvae at 24 h after treatment. Control efficacy of chlorpyrifos, thiamethoxam and bisultap was less than the first two pesticides. Changes of detoxifying and protective enzymes in P. flammans larvae were related to the kinds of enzyme and its sensitivity to pesticide after treatment with different pesticides. Compared with control, effect of beta-cypermethrin on Carboxylesterase (CarE) was the most obvious than other four pesticides; activity of glutathione-s transferase (GST) was inhibited by abamectin, while the trend was in the opposite direction for other four pesticides; activity of superoxide dismutase (SOD) was promoted by beta-cypermethrin and chlorpyrifos, and inhibited by abamectin and bisultap; Activity of catalase (CAT) was promoted by beta-cypermethrin, chlorpyrifos and bisultap, inhibited the influence of promotion by thiamethoxam. Results suggested that P. flammans larvae could be effectively controlled by beta-cypermethrin 10 mg/L and abamectin 25 mg/L with alternate spray, which could prevent the resistance to pesticides in this pest.