The invention discloses a high-thermal-conductivity heavy-duty car exhaust pipe. The high-thermal-conductivity heavy-duty car exhaust pipe comprises an exhaust pipe silencing tube, a silencing tube cover plate, silencing partitions, an automobile tail gas exhaust tube and an automobile tail gas inlet tube, wherein one end of the exhaust pipe silencing tube is sealed and the other end of the exhaust pipe silencing tube is open; the silencing tube cover plate is arranged at the open end of the exhaust pipe silencing tube; the two silencing partitions are arranged in the exhaust pipe silencing tube for dividing the exhaust pipe silencing tube into three exhaust silencing chambers; ventilating through holes are formed in the silencing partitions; the two exhaust silencing chambers at the two sides are filled with sound-absorbing materials; the sound-absorbing materials comprise flame retardant carbon fibers and glass fibers in a mass ratio being 1 to 4; filament diameters of the glass fibers are 20 microns; and filament diameters of the flame retardant carbon fibers are 35 microns. The high-thermal-conductivity heavy-duty car exhaust pipe can increase an emission rate of heat of automobile tail gas, so that the noise elimination effect of the automobile tail gas is improved.