To fabricate a platelet-compatible polymer, phosphorylcholine (PCe) was introduced onto the surface of polyethylene (PE) using a novel synthetic process. Acrylic acid was graft-copolymerized on the surface of PE by UV irradiation, using both the peroxide preirradiation and the simultaneous methods. Benzophenone and Michler＇s ketone were used as an initiator and sensitizer in this investigation, respectively. To investigate the spacer effect on the platelet compatibility of the PE membrane surface, PCe with various spacer lengths was :introduced onto the surface of PE by a series of chemical reactions. Ethylene glycol, butanediol, poly(propylene glycol), and poly(tetramethyl glycol) were used as space:rs. The modifications of the PE membrane surface were analyzed by contact-angle, ATR-FTIR, and ESCA techniques. The platelet compatibility of the PCe-modified polymer was evaluated by the in vitro platelet adherent test. It was found that the platelet compatibility of the PE film surface was affected by the existence of various functional groups on the film surface. The length of the lipophilic spacer between PCe groups and the PE surface will affect the biomimetic properties of the membrane surface.