In this study, poly (vinylpyrrolidone-acrylonitrile-vinylpyrrolidone) (PVP-AN-VP) was synthesized by three-step solution free radical polymerization. The copolymer could be directly blended with polyethersulfone (PES) using NMP as a solvent, and then PES hollow fiber membrane was prepared by using dry-wet spinning technique based on a liquid-liquid phase separation technique. Adding the copolymer could effectively reduce the BSA adsorption and suppress the platelet adhesions. Meantime, the antifouling property of the membranes increased with the increase of the copolymer amounts. Furthermore, activated partial thromboplastin time (APTT) of the modified PES hollow fiber membrane increased by 50 % compared to that of pure PES membrane. The efficient surface modification by blending PVP-AN-VP copolymer suggested that the modified PES membrane have potential to be used in blood purification fields.