The invention discloses a preparation method and application of an antibacterial coating on the surface of a dental implant, belonging to the field of biomedical polymer materials. The dopamine is coated on the surface of titanium metal, and then inserted into the trigger point to trigger the ATRP polymerization reaction, and the ring-opening reaction is carried out, and then the antibacterial agent is added under mild conditions of aqueous solution and normal temperature. The antibacterial coating is modified on the surface of the titanium metal tooth post, and the antibacterial agent is attached to the surface at room temperature and in the mild condition of aqueous solution. Compared with other methods of grafting onto the surface in an organic solvent, this method has no organic solvent residue problem, high safety, is more suitable for the environment in the human oral cavity, and has a contact non-release long-term bactericidal effect.