As the demand for appropriate heat dissipation measures to improve product stability and performance continues to increase and product design becomes highly integrated, research to improve heat transfer performance while maintaining the same area or size is required. In this study, the sample-shaped aluminum plate was treated as upper-coating, and the thickness of the coating was divided into 1mm, 2mm, and 3mm, respectively, and the coating material was applied with silver, copper, and graphene. The temperature condition of the heat source was set to 473K, and heat dissipation analysis was performed under natural convection. The thermal performance was compared and analyzed through temperature distribution, flow velocity distribution, and heat flux, and it was confirmed that the high thermal conductivity of graphene compared to other materials had a dominant effect on the increase in the conduction heat transfer rate. And it was confirmed that the high surface temperature of the graphene coating also increased the heat transfer rate by convection, thereby enhancing the heat dissipation effect.