Abstract: In order to screen effective and low toxic biological pesticides, the laboratory efficacy test of four biological pesticides against the 3-5 instar larvae of Phauda flammans was carried out. The results showed that the four biological pesticides showed obvious toxicity to Phauda flammans, and the toxicity of abamectin-aminomethyl was the strongest. It had obvious toxicity after 1 day at 80000 times the concentration, and the LC₅₀ was 10.859 mg/L. The LC₅₀ of Bacillus thuringiensis, HearNPV and Beauveria bassiana were 166.619 mg/L, 121.140 mg/L and 233.848 mg/L after 10 days, 5 days and 8 days, respectively. From the perspective of the quick effect of pesticides, the content of abamectin-aminomethyl>Bacillus thuringiensis>HearNPV>Beauveria bassiana. From the perspective of the persistence of pesticides, the content of abamectin-aminomethyl>HearNPV>Bacillus thuringiensis>Beauveria bassiana. To sum up, abamectin-aminomethyl was the most appropriate pesticide with high efficiency and low toxicity for the control of Phauda flammans.