Graphene and Carbon Nanotube have been received much attention in the microelectronics application, due to their intrinsic unique performance in the thermal and electronic conduction. In this paper, a free standing three dimensional (3D) carbon nanotube (CNT)/graphene (G) hybrid material was synthesized through chemical vapor deposition (CVD) process for heat dissipation application. Scanning electron microscope (SEM) was employed to characterize the morphology of this hybrid material. Thermal test chip was designed and fabricated to test the cooling effect of this CNT/G hybrid material. The temperature of the hot spot on the chip can decreased around 10 oC with the help of this hybrid material