Lipase preparation from Aspergiilus oryzae could act on ester bonds on the surface of poly (ethylene terephthalate) fibers and a possible hydrolytic product mono (2-hydroxyethyl) terephthalate was released. After the iipase modification, there were more carboxyl groups on the treated poly (ethylene terephthalate) fabric surface that resulted in binding with mote cationic dyes. Increased hydrophilicity and antistatic ability of poly (ethylene terephthalate) samples were found based on moisture regain, water contact angle and static half decay time.