The invention discloses a lithium ion battery anode material and a preparation method thereof. The anode material comprises lithium nickel manganese oxide, and is doped with one or more metal Xs, wherein the metal Xs are one or more of lutetium Lu, ytterbium Yb, gallium Ga and zirconium Zr; the chemical general formula of the anode material is LiNi0.5Mn1.5-aXaO4, wherein a is larger than 0 and smaller than or equal to 0.03. The lithium ion battery anode material prepared through the preparation method is uniform in element mixing, regular in structure and good in cycle performance, so that the performance of a lithium ion battery is improved.