Poly(N-vinyl pyrrolidone) (PNVP) was covalently grafted onto the surface of biomedical poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) elastomer via a technique of UV-induced graft polymerizationcombined with plasma pre-treatment. The surface graft polymerization of N-vinyl pyrrolidone (NVP)was confirmed by ATR-FTIR and XPS. Effect of the parameters of graft polymerization, i.e., the initiatorconcentration, the UV irradiation time and the monomer concentration on the grafting density was investigated.The morphology and the wettability of the PNVP-modified surfaces were characterized by AFMand DSA, respectively. Protein adsorption and platelet adhesion were obviously suppressed after PNVPwas grafted onto the SEBS substrates.