Graft copolymerization of 2-hydroxyethyl methacrylate (HEMA) as attempted onto the surface of silicone rubber membrane, which was pretreated by Ar-plasma, then exposed in oxygen to introduce a peroxide group. The effect of the amount of HEMA grafted on Ar-plasma-treated and graft copolymerization was examined for various parameters of power, pressure, time, reaction time, and concentration of HEMA aqueous solution. The surfaces were characterized by ATR-FTIR, ESCA, contact angle, and SEM, PHEMA was indicated by ATR-FTIR and ESCA analysis to be present successfully onto the grafted surface of silicone rubber membrane. The stable wettability, as demonstrated once the PHEMA grafted films, indicated contact with a hydrated environment by the study of contact angle.