The invention discloses a preparation method of a 
calcium carbonate film layer on the surface of a biomedical degradable 
metal material, belonging to the technical field of biomedical 
coating material preparation. The preparation method comprises the following preparation steps: pretreating the surface of a medical 
metal material through waterproof 
abrasive paper; mixing 
calcium salt, 
carbonate, an additive and water to prepare a 
mixed solution, and adjusting the pH value of the 
mixed solution; and immersing the pretreated 
metal material into the prepared 
mixed solution, and keeping a constant temperature for a certain time to form a 
calcium carbonate film layer on the surface of the metal material. According to the invention, the 
calcium carbonate film layer prepared by using the inorganic 
magnesium salt and the organic molecular additive is controllable in morphology, uniform and compact, good in 
binding force with a metal material matrix, excellent in 
biocompatibility, 
biological activity and biodegradability, and capable of remarkably improving the 
corrosion resistance of the metal material; and meanwhile, the preparation method is simple, mild, green, environment-friendly and low in cost, and has the prospect of being applied to biomedical metal materials on a large scale.