The invention relates to a heat conduction material co-extruded with an optical diffusion material, and a preparation method thereof, and relates to the field of polycarbonate composite materials. The heat conduction material is prepared by a polycarbonate (PC) resin, a compatilizer, a high heat conduction filling material, an oxide heat conduction filling material, a reinforcing agent, a coupling agent, an anti-oxidant and a processing auxiliary agent. The mass percentage of each component is as follows: 45-65 parts of the PC resin, 3-5 parts of the compatilizer, 0-5 parts of the high heat conduction filling material, 25-35 parts of the oxide heat conduction filling material, 0-8 parts of the reinforcing agent, 0.2-1.0 parts of the coupling agent, 0.2-0.5 part of the anti-oxidant and 0.3-1.2 parts of the processing auxiliary agent. The heat conduction material prepared by the method has excellent heat conduction performance and mechanical performance, can be co-extruded with an optical diffusion PC and processed into an LED fluorescent tube.