<p>Compared with other metal implants, titanium (Ti) has become the preferred material for human hard tissue substitutes and restorations because of its high specific strength, low elastic modulus, excellent corrosion resistance, and good biocompatibility. However, under natural conditions, a thin coating with biological inertness forms on the surface of titanium and its alloys, which reduces the biological activity of the surface. Therefore, surface modification is required before the implantation of this biologically inert material into the human body to increase its surface biological activity. Currently, increasing the biological activity of a material on its surface can increase its biological activity. In this study, we prepared magnesium titanium dioxide (MMg) coatings on pure titanium surfaces via microarc oxidation. The surface properties of the coatings were evaluated by scanning electron microscopy, energy-dispersive spectroscopy, x-ray diffraction, profilometry, and an electrochemical workstation. The biological activity of the magnesium titanium dioxide coating was subsequently evaluated through cell experiments. The results showed that the magnesium titanium dioxide coating on the titanium surface had a microporous structure and that magnesium was uniformly doped on the coating surface. The magnesium titanium dioxide coating improved the surface morphology of titanium, and the porous structure increased the surface roughness of titanium. The magnesium titanium dioxide coating not only has a good surface morphology but also increases the adhesion and proliferation of MC3T3-E1 cells. It is feasible to prepare magnesium titanium dioxide coatings on titanium surfaces by microarc oxidation. These coatings have good surface morphology and biological activity and can be widely applied in clinical practice.</p>