The invention provides a high-thermal conductivity ceramic product and a preparation method thereof. The high-thermal conductivity ceramic product is prepared by the following raw materials in part byweight: 35-40 parts of kaolin, 37-42 parts of spodumene, 15-23 parts of lithium oxide and aluminum oxide mixture, 13-17 parts of black talc, 17-25 parts of bentonite and 3.5-6 parts of boron nitridefibers. The mass ratio of lithium oxide to aluminum oxide in the lithium oxide and aluminum oxide mixture is 1:(1.5-2.2). The high-thermal conductivity ceramic product provided by the invention is excellent in thermal conductivity, small in thermal expansion coefficient, good in thermal shock resistance and high in compressive strength.