Abstract: The purpose of this experiment was to reduce the amount of chemical pesticides and to delay the drug resistance of pests. We used the uniform design experiment to mix the biological pesticide and chemical pesticide with Dalbergia odorifera leaves treated by leaf dipping method and feeding 2nd instar larvae of Orvasca subnotata, and the optimization model, the maximum cotoxicity coefficient and the best mixing ratio were obtained. The results showed that 5 kinds of tested pesticides have insecticidal effect, the avermectin LC50=212mg/L, so it was most toxic. The larvae was most sensitive to lambdacyhalothrin. After screening, composite of Bacillus thuringiensis and lambdacyhalothrin & composite of Helicoverpa armigera nuclear polyhedrosis virus and lambdacyhalothrin have good synergistic effect and the proportions were 4∶3 and 106∶3.