Abstract: Four forms of pyrethroid microcapsule were prepared with the inner interfacial polymerization method. Accoring to biological determination and releasing capacity analysis, the result showed that the acute oral toxicity of warm-blooded animals had decreased by a big margin as compared with the same dosage of emulsifiable concentrate. Determination of pesticide effect on Monochamus alternatus Hops, and residue analysis showed that the valid term of pesticide microcalsule had doubled or so, the residual amount had increased as compared with emulsifiable concentrate and had a regulate time for constant releasing.