A nanoplate-like alpha-Al2O3 out-layered Al2O3-ZrO2 coating was fabricated on Zr substrate by micro-arc oxidation (MAO). The structure, formation mechanism, anti-wear property and aging behavior of the coating were explored. The obtained results show that the coating is composed of Al2O3 and ZrO2; the amount and crystallinity of Al2O3 increase gradually from inner layer to the coating surface; monoclinic ZrO2 (m-ZrO2) and tetragonal ZrO2 (t-ZrO2) are both present in the coating, and the ratio of t-ZrO2/m-ZrO2 increases with closing to the coating surface by a "constraint" mechanism of Al2O3; the coating surface mainly consists of nanoplate-like alpha-Al2O3, and a small amount of nanocrystallized m- and t-ZrO2. The superimposition of alpha-Al2O3 growth unit on {0 0 0 1} face should be prohibited by PO43- during the MAO process, resulting in the formation of nanoplate-like alpha-Al2O3 on the coating surface. Compared with pure Zr, the coating shows noticeable improvement in wear-resistance. For aging behavior, although more t-ZrO2 in the coating is transformed to m-ZrO2 with increasing aging time, wear loss increases slightly. It indicates that the nanoplate-like alpha-Al2O3 out-layered Al2O3-ZrO2 is a potential coating for articular head replacement. (C) 2015 Elsevier B.V. All rights reserved.