TiO₂ composite film containing P and Ca was prepared on surface of medical Ti materials by microarc oxidation with constant voltage. The effects of anode voltage on the morphology, phase constituent and Ca, P content in the oxide films were investigated by SEM, XRD and EDS, focusing on the Ca and P content disposition regularity in the oxide film surface and in intra-pore. The results show that the composite film is composed of mini-pore and anatase TiO₂ phase with lower P and Ca contents as well as Ca/P ratio, in which the Ca and P contents in the mini-pore are lower than ones in film surface with low anode voltage treatment. The mini-pore, the volume number of the rutile TiO₂ and the Ca and P contents as well as Ca/P ratio are increased with the increase of anode voltage. Ca and P contents in mini-pore is equivalent to ones in the film surface in case of high anode voltage treatment. The Ti oxidization reaction can be effectively promoted with increasing constant voltage. After MAO （micro-arc oxidation）, Ti surface porous morphology, phase constituent and Ca, P contents would have an important effect on the formation of hydroxyapatite in hydrothermal synthesis treatment.