Abstract: Graft copolymerization of a mixture of itaconic acid(IA) and acrylic acid(AA) onto plain weave fabric of trilobal PET fiber was carried out with benzoyl peroxide as initiator in aqueous solution.The PET fabric had been treated with alkali before grafting.The influential factors of polymerization,such as reaction temperature,reaction time,initiator concentration and the molar ratio of the monomer mixture on grafting were studied and the optimum polymerization conditions were determined.The formation of the grafted fabric substrate was confirmed by Fourier transform infrared spectroscopy and SEM photographs.The results indicated that as the grafting percentage increases,the grafted PET fabric exhibits enhanced moisture management performance and uptake rate of cationic dyes and the dyed grafted PET fabric has brilliant shades.