Abstract: In order to improve the polyester fiber′s wearability,it is necessary to carry out modification.This work investigated the effects of grafting temperature,the concentrations of initiator and monomer on the initial rate of graft polymerization.The rate of graft polymerization was found to depend on initiator and monomer concentrations to the 1.08st and 1.37st order respectively.Based on the assumption that single radical termination is the main way of termination reaction of grafting polymerization of polyester fiber under UV-light,the graft polymerization mechanism was proposed and the graft polymerization rate model was developed.The grafting temperature was found to obey the Arrhenius law,and the apparent active energy was 29.33 kJ/mol.