||Conventional heat radiating materials are produced by simply dispersing ceramic fillers in a polymer matrix. And it forms a heat transfer path over 50 wt% of ceramic filler, which decreases in the tensile strength of heat radiating material due to the high content of ceramic fillers. It is a barrier to commercialization. In this study, we use amphiphilic diblock copolymer which can selectively disperse aluminum oxide(Al2O3), thermally conductive filler. If Al2O3 is selectively dispersed through interaction with a specific block in a phase-separated block copolymer, Al2O3 is concentrated in a specific block. And it forms a 3D network heat transfer path by adding carbon nanotubes(CNT) to act as a heat transfer bridge between Al2O3. Therefore, the heat transfer path can be formed even at 50 wt% or less. Accordingly, it is expected to develop an electric insulating heat radiating material having lower ceramic filler content and improved tensile strength as well as thermal conductivity.