Single-crystalline Mn3O4 nanoflakes were grown on manganese sheets by one-step thermal oxidation process at 360-500 ℃ in ambient atmosphere.The sam-ples were characterized by scanning electron microscope(SEM),X-ray diffraction(XRD),Raman and transmission electron microscope(TEM).The nanoflakes with a size of 15-20 nm in thickness,～60 nm in width,and～210 nm in length are obtained at 360 ℃ for 24 h.A surface dif-fusion mechanism is proposed to explain the growth of manganese oxide nanostructures via thermal oxidation,which includes two steps:manganese oxide(MnO/Mn3O4)layers form firstly,and then Mn3O4 nanostructures grow above the upper metal oxide layer to form multi-layered structures,MnO/Mn3O4/Mn3O4-nanoflakes.The nucle-ation and growth of Mn3O4 nanostructures are related to the surface energy and different growth rates along dif-ferent crystal directions,which are controlled by the dif-fusion of the metal and gas molecule.