The present invention relates to a surface modification method for improving the hemocompatibility of biomedical metallic substrate, comprising: fixing a sulfur-containing monomolecular film on the surface of oxide layer of a biomedical metallic substrate by molecular self-assembly. The surface modification will improve the hydrophilicity and hemocompatibility of the biomedical metallic substrate in contact with the blood, and ensure that the biomedical metallic substrate is non-toxic to the endothelial cells.