We present a novel composite material of nano-carbon with the highest value of thermal conductivity 2.6 W (m K)(-1), by dispersing graphite powders and multi-walled carbon nanotubes (MWCNTs) in a polymer matrix of epoxy resin and the curing agent. Furthermore, this composite has been prepared as the heat dissipation system of high-brightness light emitting diodes (HB-LEDs), using a sandwich-structured thermal interface material (SSTIM) with metal for the inner layer and two composites for outer layers. The optimal for thermal conductivity of this thermal interface material (TIM) is 4.9 W (m K)(-1), 58% higher than that of commercial products. This promising material can increase the cooling rate and lower the energy consumption of HB-LEDs. (C) 2013 Elsevier B.V. All rights reserved.