Abstract: In this work radiation grafting of acrylamide onto polystyrene beads by peroxide has been studied and the ability for binding immunoglobulin onto chemically-treated grafted beads has been determined. The results show that the grafting reaction basically completes in three hours.At about 60℃ of grafting reaction temperature the grafting level is the highest. The grafing level is higher in low dose rate than in high dose rate when the total dose is the same.The grafting level is increased with the increasing of irradiation dose and monomer concentration. The half-life of the peroxide produced on polystyrene beads is about 50 hours under ambient temperature. Itis found that the ability for binding immunoglobulin by chemically-treated grafted beadsis higher than untreated beads and the ability is increased with the increasing of grafting level.