Epoxy resin, characterized by prominent mechanical and electric-insulation properties, is the preferred material for packaging power electronic devices. Unfortunately, the efficient recycling and reuse of epoxy materials with thermally cross-linked molecular structures has become a daunting challenge. Here, we propose an economical and operable recycling strategy to regenerate waste epoxy resin into a high-performance material. Different particle size of waste epoxy micro-spheres (100–600 μm) with core-shell structure is obtained through simple mechanical crushing and boron nitride surface treatment. By using smattering epoxy monomer as an adhesive, an eco-friendly composite material with a “brick-wall structure” can be formed. The continuous boron nitride pathway with efficient thermal conductivity endows eco-friendly composite materials with a preeminent thermal conductivity of 3.71 W m⁻¹ K⁻¹ at a low content of 8.5 vol% h-BN, superior to pure epoxy resin (0.21 W m⁻¹ K⁻¹). The composite, after secondary recycling and reuse, still maintains a thermal conductivity of 2.12 W m⁻¹ K⁻¹ and has mechanical and insulation properties comparable to the new epoxy resin (energy storage modulus of 2326.3 MPa and breakdown strength of 40.18 kV mm⁻¹). This strategy expands the sustainable application prospects of thermosetting polymers, offering extremely high economic and environmental value.