Abstract: Surface biomedical properties of plasma polymerization on medical polyurethane were studied. Hexamethylated disiloxane (MI) plasma polymerization was performed at a power of 100 W with the polymerization- time ranging from 1 to 15min. The results showed that hexamethylated disiloxane plasma polymerization resulted in an increase from 30.52 to 37.44s in the recalcification time. At the same time, the anticoagulability of polymerized samples for the polymerization time of 2-5min was 2.5 times that of the pristine. Results of x-ray photoelectron spectroscopy, electron spin resonance analysis showed that plasma polymerization decomposed some of CN bonds to form new SiN bonds and to increase the amount of radicals in polyurethane, which were the main reasons for surface modification.