The invention provides a positive electrode material of a lithium ion battery and a preparation method of the positive electrode material. The positive electrode material of the lithium ion battery isprepared from y{xLi2MnO3*(1-x)LiMO2}(1-y)C, wherein M is at least one of Ni, Co, Mn, Fe, Cu, Al, V, Mg, Te, Ti, Cr and Zr, 0.01<=x<=0.7 and 0.9<=y<=0.998. The positive electrode material provided bythe invention is different from a material prepared through a traditional element doping or coating method in which only the ion conductivity of a particle surface layer can be increased; a carbon material is used as a conductive reinforcing agent and is filled in pores of the positive electrode material, so lithium ion transfer can be promoted in the charging and discharging process, thereby remarkably improving the total ion conductivity of particles, and improving the rate capability of the lithium-rich positive electrode material.