The grafting of acrylic acid (AA) onto polyurethane (PU) films was induced by gamma-ray irradiation without degassing to obtain the PU-g-AA modified PU films. The chitosan/alginate (CA) gel was further grafted onto the PU-g-AA modified PU films by using 1-ethyl-3- (3-dimethyamino propyl) carbodiimide (EDC). The PU-g-AA modified PU films were characterized by FTIR spectroscopy. The effect of acrylic acid and CA gel grafting on the properties was investigated. The results show that the PU films exhibited were sufficiently strength and that the acrylic acid was grafted onto PU films by gamma-ray irradiation. The hydrophility of PU films significantly increased after graft polymerization with gamma-ray irradiation.