Abstract: A cross-section direction two-dimensional mechanistic model of the Siemens-Westinghouse Power Corporation’s (SWPCs) cathode-supported tubular solid oxide fuel cell(SOFC) was developed.The model coupled the intricate interdependency among the ionic conduction, electronic conduction, gas transport, heat transfer and electrochemical processes.Three forms of polarization (activation polarization, Ohmic polarization, concentration polarization) were considered.Result validation showed good agreement with the published experimental data.The simulation results predicted that the species concentration and current density distributions were related to SOFC operating conditions.The size of current collector would affect the cell performance and should be carefully chosen.Gas diffusion through a thick and porous cathode was proven to be one of the performance-limiting factors and better cell performance could be achieved through the optimization of electrode microstructure.