Highly thermal conductive and electrically insulating polymer materials are important for thermal management of numerous applications in new generation electronic devices. One of the common method to increase thermal conductivity is adding conductive fillers into the blends. By introducing of carbon based fillers both thermal and electrical conductivity increase because in carbon based materials free electrons are responsible for conduction. However, in ceramic based fillers the lack of free electrons make phonon (lattice vibration) responsible for thermal conduction, Although the thermal conductivity value is much lower than carbon based fillers. So, enhancement of the thermal conductivity without sacrificing the electrical insulation remains as a challenge. In this work, both high thermal conductivity and high electrical resistivity of immiscible Polypropylene (PP)/Polyamide 6 (PA6) blends are achieved by using Boron Nitride (BN) and Reduced-Graphene oxide (rGo) as hybrid fillers. In this study, the blends were prepared by two difference mixing sequences in order to investigate the effect of the localization of the fillers on the improvement of the thermal conductivity. The results demonstrate that the migration of rGo from PP phase into the PA phase changes the morphology of the blends and leads to increase thermal conductivity because the total interface decreases and phonon scattering decreases. In addition, the electrical conductivity test demonstrates that all the samples are electrically insulating.