The invention discloses a high-nickel ternary material with a cobalt-rich surface layer and a preparation method thereof. The method comprises the following steps: (1) preparing a cobalt chloride solution by spray pyrolysis to obtain porous spherical Co3O4; (2) uniformly mixing the porous spherical Co3O4 with a high-nickel ternary hydroxide precursor and lithium salt, and then sintering the mixture to obtain a nickel-based ternary anode material with the cobalt-rich surface layer. The surface of the anode material has a uniform cobalt-rich coating layer, and reaction of Ni4+ and electrolyte at the position of an interface is reduced. Meanwhile, phase change of H2-H3 is inhibited in charging and discharging processes of the material, volume change of unit cells due to phase change is reduced, therefore, a layer structure of the material is stable, and the cycle performance is improved. The raw materials used in the preparation method are simple and easy to obtain, the process is simple, and the technological process is short.