Abstract: Polystyrene（PS） coated calcium hydroxide\Ca（OH）<SUB>2</SUB>],namely Ca（OH）<SUB>2</SUB>/PSmicrospheres were successfully prepared by in-situ suspension polymerization method through adding initiator and styrene monomer into glucose-aqueous media when calcium oxide （CaO） turning into Ca（OH）<SUB>2</SUB>.Effects of glucose-aqueous solution,styrene,stabilizer-polyvinyl alcohol （PVA）,and reaction temperature on particle size and dispersion coefficient of monodisperse Ca（OH）<SUB>2</SUB>/PS icrospheres were investigated and optimal synthesis conditions were obtained.Ca（OH）<SUB>2</SUB>/PSmicrospheres with average particle size of 30~40 μm and particle dispersion coefficient of 0.08~0.10 were obtained under optimal conditions.SEM photos showed that Ca（OH）<SUB>2</SUB>/PShas good sphericity,smooth surface and no damage.Infrared spectroscopy（FT-IR）indicated that the products were Ca（OH）<SUB>2</SUB>/PS microspheres. 