The radiation induced grafting of electron beam pre-irradiated F 46 film with 4-vinylpyridine in the vapor phase was studied. The grafting process was carried out in a reactor with recycling monomer, which produced the saturated vapor of 4-vinylpyridine. The F 46-4 vp grafts can be transformed into anion exchange membranes by post-treatment.,Results of experiments showed that: (1) The grafting process of F 46-4 vp system was very similar to that of F 46-st system, at the first stage grafting proceeded slowly; and the second stage was characterized by the increase of percentage graft; at the final stage the percentage graft became levelled off. (2) The elongation of F 46-4 vp grafts varied with the percentage graft correspondingly. (3) Anion exchange membranes prepared by above mentioned method exhibit good physical and chemical properties. (4) Grafting in gaseous phase with recycling monomer seems to be effectual.