Abstract: The application of low temperature argon plasma technology to improve the hydrophilic ability of PET was studied.The influences of different plasma working parameters(discharge power,duration of discharge and working pressure) on the water contact angle of PET were analyzed.IR and SEM were used to examine the morphological change of the treated PET samples.The results show that the change rule of water contact angle on the surface of PET film varies with the working parameter.After plasma treatment the quantities of CO and CC bonds on the surface of modified PET are increased,while ester radicals are decreased.And the wettability of PET was remarkably improved by argon plasma.However,time-series image change of the fiber surface of low temperature argon plasma treated PET is apparent.