In this paper, we investigated the change of wettability, surface potential decay and dielectric properties caused by ultraviolet-treated, thermal-treated and discharge-treated FRP(fiber reinforced plastics) respectively for finding out: the influence of dry treatments effected to electrical characteristics on the surface of polymer composites. For the change of wettability, the contact angle of thermal-treated specimen with the high temperature of 200℃ increased. But that of UV-treated and discharge- treated specimen decreased. The characteristic of surface potential decay shows the tendency of the remarkable decrease on UV-treated and discharge-treated specimens, but no difference on thermal-treated specimen compared with untreated one. Also, for the dielectric properties, it shows the increase at large on the treated specimens and especially, the remarkable increase on thermal-treated one.