Preparation of biodegradable microcapsule using a poly lactic acid as wall material was performed by (W/O/W) emulsion solvent evaporation method. Fractional entrapment of the core material and the average diameter of the microcapsule are independent of the composition of the inner aqueous phase, such as salt concentration, pH and viscosity. On the other hand, by changing the salt concentration of the outer aqueous phase and the hold up of dispersion phase in the (W/O) emulsion, it is possible to increase the fractional entrapment of the core material with the increase in (W/O/W) emulsion stability and amount of wall material. The entmpment effect is controlled by preparation conditions.