The graft-polymerization of MAA on the surface of the modified particles APMS-SiO2 was carried out in a solution polymerization system. The modified particle APMS-SiO2(1.5g)were added into a four-necked flask equipped with a mechanicle agitator, a reflux condencer, a thermometer and N2 inlet, followed by adding 100ml of distilled water and 5ml of monomer MAA. the content was stirred and the modified particles APMS-SiO2 were dispersed fully. N2 was bubbled for 30min to exclued air. The content was heated to 40C,and 0.055g of initiator APS was added. the graft polymerization was performed under N2 atmosphere at 40C for 10h. The resultant particles were extracted with ethanol in a soxhlet extractor for 24h to remove the polymer attaching physically to the particles PMAA/SiO2 were obtained.