Using polylactic acid (PLA) as wall and ethyl menthane carboxamide (EMC) as core substance, microencapsulated EMC (MEMC) agents were prepared based on solvent evaporation method. The structure and morphology of MEMC were analyzed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and laser particle size analyzer. The MEMC agents had a mean diameter of about 1020 m. Moreover, the thermal properties of the MEMC agents were measured by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The melting point and thermal stability were improved due to the encapsulation of PLA resin. In addition, polyvinyl alcohol (PVA) and PLA concentration, stirring rate, and oil/water ratio were investigated for their effects on the particle size. As demonstrated by experimental results, the diameters of the microcapsules decreased with increasing stirring rate and oil/water ratio, and increased with increasing PLA concentration. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013