By the direct radiation grafting teehoniqlle．kinetics of the Garama-induced graft eopolymerization of st-AA to p01ytetrafluoroethyene has been studied at 20°—40℃．Dependence of the grafting temperature on the critical radiation intensity has been found．Above a given critical radiation intensity，the grafting is limited to the surface．Below that intensity，the grafting proceeds in the mass．Optical microscope and scanning electron microscope were used to study the structure of the cross section and surface of the grafted film．The grafted amount of the surface grafted film is about 1 mg／cm2，thus，the average adhe~ve strength is found to be above 100 kg／cm2．The electrical properties of the surface grafted film are the same as those in nongraft film．This indicates that the Garoma radiation．induced surface graft copolymer of st-AA to polytetrafluoroethyene could be used as constructional material with strong adhesive strength or as adhesive sealing material of the electronic parts．