A new carbon foam with high thermal conductivity and light density is prepared by thermal treating of coal tar based mesophase pitch, 500℃, 6~8MPa pressure.The max thermal conductivity can up to 110W/(m·K). The thermal conductivity is increased from 77.5W/(m·K) to 110W/(m·K) when the mesophase pitch increased from 0% to 100%. The soaking time and pressure also have influence on it.