The aerosol solvent extraction system process (ASES), which is one of the supercritical anti solvent processes (SAS), was used to produce poly(L-lactic acid) (PLLA) into the submicron particles. Dichloromethane (DCM, CH2Cl2) and carbon dioxide were selected as a solvent and as an antisolvent for PLLA, respectively. The objective of this study was to investigate the effect of the various process parameters such as temperature, pressure, and solution concentration on PLLA particles. With increasing temperature and pressure, particle size was increased. Also, higher PLLA concentration led to larger particle size and broader particle size distribution. A scanning electron microscope (SEM) was used to observe the morphology and size of PLLA particles recrystallized by ASES process. The mean particle size and its distribution of processed particles were measured by using a laser diffraction particle size analyzer (PSA).