Graphite flakes and silicone carbide particles are used as heat conductive fillers added into methyl vinyl silicone rubber, and the effect of filler amount, filler shape and different curing agents (DCP, DBPMH) on the thermal conductivities of silicone rubber are investigated in this article. The results reveal that the thermal conductivities of composite silicone rubber will be increased with the increase of the amount of fillers. While the filling content surpasses a certain value, the thermal conductivity of composite increases obviously. The silicone rubber filled with graphite flake possesses a higher thermal conductivity than that filled with silicone carbide particles at relative high fillers content, but both of them are close to each other at relative low fillers content. Moreover, the thermal conductivities of composite silicone rubber filled with the powder form curing agent (DCP) are better than that of composite silicone rubber filled the liquid form curing agent (DBPMH).