With the performance improvement and size reduction of electronic equipment, the internal circuit power consumption increases and heat is generated too much. The accumulation of heat will affect the stability, durability, and service life of electronic equipment. Therefore, efficient heat dissipation is the mainstream thinking direction to solve this problem. This experiment uses the synergetic effect of two particles. With epoxy (EP) resin as the matrix, boron nitride nanoparticles are coated with polydopamine (PDA), and the hydroxyl group on the surface of PDA is modified with coupling agent. The sulfhydryl group on the coupling agent is combined with silver (Ag) nanoparticles, and finally the epoxy resin composite containing boron nitride‐polydopamine‐silver (BPA) core–shell structure is obtained. With 15 wt%. BPA filler, the thermal conductivity of this material is 0.275 W/mK, 1.54 times that of pure epoxy resin 0.179 W/mK. The breakdown strength is 8.931 kV/m, 1.05 times that of pure epoxy resin 8.493 kV/m. The impact strength is 4.06 kJ/m2, 1.37 times that of pure epoxy resin 2.97 kJ/m2. At the same time, the shape of this material has good customization and is expected to be applied in the field of thermal management materials. [ABSTRACT FROM AUTHOR]