The invention provides a lithium ion battery cathode material and a preparation method thereof and a lithium ion battery. The cathode material is of a core-shell structure, the core is graphite, and the shell is of a two-layer structure which sequentially comprises an inorganic lithium layer and an organic lithium composite layer from inside to outside. The preparation process of the cathode material comprises the steps that 1, the graphite and an inorganic lithium composite liquid are mixed to be uniform, after the pH value is regulated, heating is conducted to remove an organic dispersing agent and solvent, and grinding is conducted to obtain a solid product A, wherein the inorganic lithium composite liquid is prepared from inorganic lithium, the organic dispersing agent, an adhesive, graphene and the solvent; 2, the solid product A and organic lithium composite liquid are mixed to be uniform, drying and carbonizing are conducted sequentially, a product is cooled to room temperature, and then the cathode material is obtained, wherein the organic lithium composite liquid is prepared from organic lithium, a dispersing agent, an adhesive, carbon nanotubes and solvent. According to the cathode material, the transmission rate of lithium ions is effectively increased, the electron conductivity of the lithium ions is effectively improved, quick charging and discharging are well achieved, and finally the rate performance, safety performance and cycle performance of the battery are improved.