The present paper presents the results of surface modifications of biomaterials using plasma immersion ion implantation (PIII) in Institute of Surface Modification of Biomaterials in Southwest Jiaotong University. In the research, titanium oxide films and diamond-like carbon (DLC) films doped with different elements, as well as surface modification of polymers, are prepared using PIII. The blood compatibility of the films is investigated. Significant improvement in blood compatibility of the films compared with those untreated substrate materials is confirmed. The mechanisms of the blood compatibility of the films are discussed. The results show that the energy band structure of the material surface may be a controlling factor in the blood compatibility of the material. A film with an n-type semiconductor nature would have a better blood compatibility. Improvement in wear resistance of hip joint and modification of antibacterial property of artificial heart valve suture ring material is also presented in the paper.