The invention is applicable to the technical field of lithium ion battery cathode materials. The invention provides a high-voltage low-impedance high-safety lithium cobalt oxide cathode material and apreparation method thereof. According to the invention, on the basis of lithium cobalt oxide doping, a layer of solid electrolyte Li14Zn(GeSxO4-x)4 with an LISICON structure coats the surface of thelithium ion battery cathode material, compared with a traditional oxide and other solid electrolyte coating materials, the solid electrolyte coating material with the LISICON structure has the advantages that the Li+ conductivity is high, the structure is stable, there is no reaction with the lithium metal and the like. The solid electrolyte with the LISICON structure is used as a coating, so thatthe safety can be improved, the impedance can be reduced, the rate capability can be improved, the solid electrolyte can be well applied to the next generation of solid-state batteries, a solid-phasesintering method is adopted, the process is simple, the cost is low, and the high-voltage low-impedance high-safety lithium cobalt oxide cathode material and the preparation method thereof are suitable for industrial production.