Many kinds of mite was caused by allergy and sick house syndrome, so it has become one of the social problems. Farnesyl acetone is one of the most potent anti-mite agent. However the vapor pressure of farnesyl acetone is high even at room temperature. This indicates the anti-mite effect has not been sustained even though the agent has strong anti-mite effect. In this study, we attempted to prepare polylactide microcapsule with farnesyl acetone for the purpose of sustainable dosage form of anti-mite agent. Microcapsule was prepared by solvent evaporation, which was a method of microencapsulation. The effects of preparation conditions on the enclosing efficiency, the release of microcapsule and anti-mite effect of microcapsule were investigated.