The present invention relates to a microphere preparation method using modified polylactic acid material as capsule material. Said preparation method includes the following steps: firstly, the capsule core material can be dissolved or dispersed in the water, the modified polylactic acid material is dissolved in the solvent which can be mixed with water-phase; then the aqueous solution of capsule core material is added into the solution of modified polylactic acid material or the solution of modified polylactic acid material is added into the aqueous solution of capsule core material or said two solutions are simultaneously added into the solvent capable of dissolving polylactic acid material or their mixed solution is added into the solvent capable of dissolving modified polylactic acid material, then they are stirred so as to obtain microsphere solution, filtered to obtain microspheres. |