© 2019 Elsevier LtdEpoxy resin is a common adhesive bonding material used to join dissimilar materials, especially in the electronics and aerospace industries. However, its low thermal conductivity and high coefficient of thermal expansion limit the direct use of epoxy in practical applications. In order to improve thermo-mechanical properties, we have prepared a series of epoxy composites using a binary system of hexagonal-boron nitride (h-BN) and aluminum oxide (Al2O3) fillers and analyzed the effect of the ratio of these fillers on the thermal conductivity of composites. While h-BN platelets form the main thermal conductive network, Al2O3 nanoparticles bridge the separated h-BN platelets to build more thermal conductive pathways. We proposed the improving of thermal conductivity as well as the mechanical properties of the epoxy matrix by incorporating h-BN and Al2O3 fillers at an optimum ratio.