The invention discloses an oxide material containing Mg, Cu and Mn and a preparation method and an application of the oxide material. The chemical general formula of the oxide material is Na(0.8+alpha)MgxCuyM(1-x-y-z)MnzO2+beta, M is an element for doping and substituting a transition metal site and specifically comprises one or more of Fe<3+>, Zn<2+>, Ni<2+>, Li<+>, Al<3+>, B<3+> and Ti<4 +>, thevalence of a transition metal element Mn in the chemical general formula is +4, alpha, x, y, z and beta are mole percentages of corresponding elements respectively, the relationship among alpha, x, y, z, and beta satisfies (0.8+alpha)+2x+2y+4z+m(1-x-y-z) =2(2+beta) and 0< = (1-x-y-z), 0.02<= alpha <=0.2, x > 0, y > 0, z > 0, -0.02 <= beta<= 0.02, m is the valence state of M, 1<= m<= 4, the oxidematerial is an O3-phase layered oxide material, and the space group is R3<->m