Abstract: In order to study the effect of the micro-structure of the material surface on its anti-coagulant characteristics, the micro-structures were fabricated on pyrolytic carbon, the most popular material of heart valves, with nanosecond laser. The micro-structures coated with silylation were periodic micro-holes and micro-gratings. The topographies were characterized by scanning electron mircoscopy, the surface chemical composition was characterized by X-ray diffraction, the surface energy was characterized by contact angle machine, and the anti-coagulant characteristics were measured. The results show that the chemical composition is the same between the micro-structure surfaces and the smooth surfaces, the micro-structure surfaces have the super hydrophobicity and the low surface energy. Comparing with the smooth surface, the micro-structure surface has less platelet adhesion, fewer clusters, fewer deformation and better anti-coagulant property. The results are helpful to improve the anti-thrombotic characteristics of the artificial heart valves by surface modification.