Degraded glass ceramic thin film for medical magnesium alloy surface and preparation method of degraded glass ceramic thin film

The invention relates to a degraded glass ceramic thin film for a medical magnesium alloy surface and a preparation method of the degraded glass ceramic thin film. The thin film is composed of CaO-PoO5-Na2O-MO, wherein the mol ratio of Ca to P is 1, M is one or combination of more selected from Zn, Sr, Mg, Ag, Ti and Al, the mol percentage of MO is 1-5%, the CaO-PoO5-Na2O is based and the ratio of Ca to P is controlled to be equal to 1; stable gels with various components are prepared by adding one or two different metal ions; a gel layer is evenly coated on the surface of a magnesium alloy substrate by dipping-lifting, and finally, the uniform and compact glass ceramic thin film is obtained after drying and heat treatment. The glass ceramic thin film prepared by using the method not only has excellent biological activity and degradable ability, but also has a controllable degrading rate; the degrading rate can be adjusted to be matched with the growth rate of a bone tissue to be restored, and therefore, various clinical demands are met.