Zwitterionic polymer of poly(sulfobetaine methacrylate) (PSBMA) was grafted from polysulfone (PSf) membrane via surface initiated atom transfer radical polymerization (SI-ATRP). The polysulfone-graft-poly(sulfobetaine methacrylate) (PSf-g-PSBMA) membrane was characterized by scanning electron microscopy (SEM), atomic force microscopy (REM), attenuated total reflectance Fourier transform infrared spectra (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and static water contact angle (WCA) measurement. The membrane showed excellent protein antifouling property though the water flux decreased to some content; nevertheless, the protein rejection ratio of the modified membrane was nor change. The biocompatibility of the membrane was characterized by protein adsorption, hemolysis assay, platelet adhesion, plasma recalcification Lime, activated partial thromboplastin time (APTT), thrombin time (TT) and cytotoxicity experiments, and the results indicated that the modified PSf membrane had good blood compatibility and cytocompatibility. (C) 2013 Elsevier B.V. All rights reserved