Abstract: This paper mainly deals with the process of the contacted breaking release microcapsules of pesticide, by means of coacervation and interfacial poly merization five kinds of microcapsules prepared with fenvalerated_fenthion (FF) and wall polymers polyaminoresin (P), gelation_gum acacia (G1) were used to control fests on Monochamus alternatus Hope and Dendrolimus punctatus (Walker) overwintering larva. The results show that 17.5％ polyaminoresin microcapsules can maintain the original shape without self_breaking in the environment in one month unless being contacted by insects. The gelation_gum acacia and polyaminoresin microcapsules （6％ and 15％ wall meterials respectively) can keep mortality to D.panctatus (Walker) by 90％ in 25 days. This kinds of microcapsules are promising to control forest pests especially longhorn_beetles.