With polylactic acid (PLA) resin as walls and capsaicin as core substances, microcapsules were prepared based on diphase emulsion method. The microcapsule characteristics such as the particle size, inner structure and properties were investigated. The morphology and size distribution of the microcapsules were analyzed by laser particle size analyzer and scanning electron microscopy (SEM). The microcapsules had a mean diameter of about 60~120 µm. In addition, their thermal properties were measured by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was demonstrated that the melting point and thermal stability were improved or changed compared with that of the pure capsaicin. These phenomena were caused by the encapsulated PLA resin over the surface.