The conjugate heat transfer from combustion in furnace to supercritical fluid in tube has been numerically investigated in this study. The mathematic model of the conjugate process has been constructed. The effects of the combustion status in furnace on the conjugate heat transfer process were analysed. The results demonstrate that the heat transfer deterioration of supercritical fluid in the tube will only occur in high heat flux regions such as the high temperature recirculation zone. The swirling air can suppress the high temperature recirculation zone near the furnace wall, which is beneficial to inhibit the heat transfer deterioration of supercritical fluid in the tube.