Abstract: Novel modified polymeric materials are provided. The polymeric materials according to the invention are prepared by grafting a fluorine-containing compound onto a polyurethane polymeric substrate. The polymeric materials show superior blood compatibility in the in vitro and ex vivo tests, attributing to hydrophobic property, inertness and water-repelling property intrinsic to the grafted fluorine containing compounds.The polymeric materials according to the invention are useful as the materials for the artificial, circulatory, internal organ systems to be contacted with blood, such as artificial hearts, artificial blood vessels, artificial heart valves, artificial blood oxygenators, and artificial kidneys, or for the medical devices/instruments to be inserted into the blood vessels, such as vein catheters, artery catheters and intra-aortic balloon pumps.