The invention discloses a biological coating and a dental arch wire coated with the same, and belongs to the technical fields of surface modification of biomedical metal materials and medical equipment. The biological coating comprises Ti and Nb serving as main components, and also comprises at least one of tin, aluminum, silicon, zirconium, tantalum, hafnium, palladium, gallium, nickel and oxygen. The invention provides the dental arch wire which uses a TiNbAl titanium alloy serving as a base material and is coated by the coating. Medical equipment products coated by the coating have good biocompatibility and good corrosion resistance and great improvement on superelasticity, shape memory effect, fatigue performance and other composite properties, and can be used in the field of medical treatment serving as functional coatings on surfaces of super-elastic stents, orthodontic dental arch wires, orthopedic implant equipment and the like. The dental arch wire has lower elastic modulus, excellent biocompatibility and mechanical compatibility; and the base material of the dental arch wire has excellent mechanical performance, corrosion resistance, and can be subjected to large deformation cold machining, such as cold rolling, cold wire drawing and the like.