Abstract: Taking natural gas as the fuel, an external reforming experimental platform of solid oxide fuel cell (SOFC) system was established, so as to test the performance of the SOFC stack under different reforming conditions, and to analyze the effects of following factors on the stack performance, such as the water-carbon ratio, reforming temperature, reforming mode and natural gas flow, etc. Results show that under different current densities, the power output of SOFC stack using steam reforming is higher than that using auto-thermal reforming. When the stack working temperature is constantly set at 1 023 K, the power output of SOFC stack gradually increases with the rise of steam-carbon ratio, which significantly improves with the rise of natural gas flow.