AbstractThe high demand for thermally conductive materials in the housing and packaging industry of electronic device highlights the necessity for the development of novel thermal conductivity materials. In this study, waste poplar wood was delignified and combined with boron nitride (hBN) to establish a blend system with a cross thermally conductive network. Using the vacuum‐assisted resin transfer molding process, a biobased composite material was prepared with high thermal conductivity (1.41 W m⁻¹ K⁻¹), mechanical strength (flexural strength of 100.7 MPa and tensile strength of 40.0 MPa), flame retardancy, and water resistance. Compared with raw wood, the incorporation of hBN increased the thermal conductivity of the prepared material by 1324.2%. The high thermal conductivity performance surpassed that of most polymers and elastomers commonly used in electronic component heat dissipation materials, indicating the enormous potential of the prepared composite material in the field of heat dissipation materials.