The invention relates to the technical field of surface treatment and especially relates to a surface treatment method for improving bioactivity of a medical beta-type
titanium alloy surface. The surface treatment method is characterized in that through
anodic oxidation, hydro-
thermal treatment and heating treatment on a
titanium alloy, a
composite oxide coating is formed on the surface of the
titanium alloy; an inner layer is an
oxide nanotube layer; the contents and element valences of Ti, Nb and Zr oxides of the inner layer change gradually; the
diameter of the inner layer is in a range of 30 to 310nm; the thickness of the inner layer is in a range of 0 to 20 microns; and an outer layer is a
calcium titanate layer having the thickness of 0 to 1 microns. The surface treatment method is suitable for a beta-type medical
titanium alloy rich in Nb, Zr and the like. A gradient
coating prepared by the surface treatment method has an integrated
crystal form, has a high bone hydroxyapatite layer formation induction capacity and a
high cell absorption and proliferation capacity of the surface, and has good
biocompatibility. The surface treatment method can prevent the
phase change and the brittle rupture caused by high temperature spaying. An
oxide layer membrane is directly formed on a matrix by chemical and electrochemical principles so that the adherence between the matrix and the
oxide layer membrane is improved. Through the surface treatment method, a uniform
coating layer can be formed on a matrix having a complex shape without the limit of a matrix shape.