Silk fabric samples were grafted with 2-hydroxypropyl acrylate monomer by ultraviolet rays, and a light-initiated graft copolymerization system without any additives or co-additives has been established. Experiments were performed to study the effects of monomer concentration, irradiation time, pH value, and reaction temperature on the grafting rate. FT-IR and DSC characterizations of the grafted silk samples were carried out to study the property changes in the silk fabrics. With advantages of fairly high graft rate, simpler equipment and operation, free of additives, and less homopolymer, the method can be an effective technique to improve the properties of silk fabrics.