Hybrid polymer compounds have become modern times, as their applications have increased, especially those reinforced with fibers and molecules due to their high performance, which allows them to be used in different applications. In this research, the dependence of the thermal conductivity and density of epoxy compounds on the volume fraction ratio of the reinforcements including carbon fibers, silicon carbide and alumina will be discussed. new hybrid epoxy compounds have been developed. The epoxy compounds reinforced with plain weave carbon fibers with different volume fractions of micro-particles of silicon carbide and alumina were prepared by hand lay-up. The physical properties including thermal conductivity and density of hybrid epoxy compounds were determined experimentally. The results showed an increase in the thermal conductivity by increasing the proportion of silicon carbide and alumina without affecting the density of the epoxy compound. This high improvement in thermal conductivity with low density in these hybrid epoxy composites have been driven them as possible nominations for electronic devices. The optimum content of hybrid epoxy composite for electronic applications is at SiC 10% and Al2O3 5% with 15 carbon fiber and 70 epoxy. Thus, a new polymer-based compound with improved thermal conductivity for electronic applications was produced.