Abstract: The grafting copolymerization of styrene-divinylbenzene onto polypropylene fiber by 60Coγ-rays was carried out and several influence factors were studied. With the increase of the amount of materials in the test，the dose rate of radiation should be diminished to assure that the graft polymerization reaction could be carried out smoothly and uniformly. When dose rate was 0.8 kGy·h－1 and reaction time was 7 h，the intake yield of products was 280%～293% and the products had good mechanical property. Methanol as solvent can be reused. Strong acidic ion-exchange fiber was prepared by sulfonating the grafted copolymer with sulfuric acid and its exchange capacity was 3.7～4.2 mmol·g^－1.