The invention discloses a high-nickel ternary positive electrode material coated with a fast ion conductor, a preparation method thereof, and a lithium ion battery prepared from the material. The basematerial of the high-nickel ternary positive electrode material coated with the fast ion conductor is LiNi1-x-yCoxMnyMzO2, wherein x is more than 0 and not more than 0.15, y is more than 0 and not more than 0.15, z is not less than 0 and not more than 0.1, and M is any one or more of Al, Mg, Co, Ni, Ti, Fe, Zr, and Sn; and the chemical general formula of the fast ion conductor is Li1+aAaD2-a(PO4)3, wherein A is any one or more of Al, Cr, Ga, Fe, Sc, In, Lu, Y, and La, D is any one or more of Ti, Ge, Zr, Sn and Hf, and a is more than 0 and not more than 1. The coating of the surface with the fast ion conductor can effectively reduce the residual lithium on the surface of the ternary positive electrode material, and reduces side reactions of the ternary positive electrode material and an electrolyte; and the lithium ion battery assembled by using the positive electrode material has a high first charge-discharge specific capacity and a high capacity retention.