The fluid state in supercritical conditions is between liquid and gas. Its diffusivity is close to gas while the density level is equal to liquid. Such special characteristics lead to a different pattern in heat transfer under supercritical pressure conditions compared to subcritical pressure situations. According to the heat transfer properties of water, carbon dioxide as well as carbon and hydrogen fuels under supercritical conditions, this paper gives an analysis on supercritical fluid heat transfer characteristics, and summaries the influences of the physical factors (buoyancy, heat flow density, mass flow, pressure and inlet temperature) on fluid heat transfer properties, in which the buoyancy, heat flow density and mass flow are dominant factors. This paper also makes a comprehensive analysis of supercritical fluid heat transfer patterns inside the tube. The enhancement and deterioration of heat transfer is closely concerned with the changes of supercritical fluid physical properties.