Biocompatibility of materials refers to the compatibility between materials and hosts, it is the important characteristics of biological materials that is different from other functional materials, which generally including histocompatibility and hemocompatibility.For those nano biomaterials that are in direct contacting with the blood, their blood compatibility is particularly important.After materials contact with the blood, the surface may make the platelet adhesion, aggregation and activation, thus resulting in thrombosis.In the research carbon nano tubes (CNTs), nano-graphite, nano-hydroxyapatite and nano-TiO2 were used as the object of study and compared their hemocompatibility of same scale materials.Moreover, hemocompatibility of different scale in each material was comparative analysis.Hemolytic test, platelet binding test and quantitative detection of different expression content of platelet specific membrane protein GPⅡb-Ⅲa were utilized to investigate the blood compatibility of the materials.The results reveal that hemolysis rates of different morphology samples were different.The morphology of platelet adhesion was different.Research and analysis show that the smaller diameter materials in the same type material have well blood compatibility in the range of our limited experimental samples, also show blood compatibility of different kinds of material with the same scale is related to material species and surface characteristics.To improve the surface hydrophilic properties of materials is conducive to improve the blood compatibility of the materials.By detecting the different content of specific platelet membrane protein GPⅡb-Ⅲa and observing platelet adhesion can evaluate the antithrombotic ability of materials with different diameter preliminarily.It will contribute to understanding the effect mechanism of platelet physiology function after incubation different materials.The results provides experimental basis in order to improve the biomedical nanomaterials blood compatibility.