The polymeric microspheres were synthesized by the precipitation copolymerization of glycidyl methacrylate (GMA) with methacrylic acid(MAA) or 2-hydoxyethyl methacrylate (2-HEMA) containing styrene (ST) in SC-CO2. Scanning electron microscopy (SEM) showed that the products were spherical microparticles, with the addition of MAA and/or 2-HEMA as the monomer, with diameter of 0.2-2 mu m. The effects of copolymerization pressure, temperature, and ratios of GMA/MAA, ST, and/or GMA/2-HEMA, on the particle size and morphology were investigated in detail. A new experiment setup is proposed for the large amount of production, based on the rule of lower monomer concentration, more stable system, and better use of the present polymerization apparatus. (c) 2006 Wiley Periodicals, Inc.