A numerical simulation tool for calculating the planar solid oxide fuel cells was described. The finite volume method was employed for the simulation, which was on the basis of the fundamental conservation laws of mass, momentum, energy and electrical charge. Temperature distributions, molar concentrations of gaseous species, current density and over potential were calculated using a single cell unit model with double channels of co-flow and counter-flow cases. The influences of operating conditions and anode structure on the performances of SOFC were also discussed. Simulation results show that the co-flow case has more uniform temperature and current density distributions and smaller temperature gradients, thus offers thermostructural advantages than the counter-flow case. Moreover, in co-flow case, with the increasing of delivery rate, temperature and hydrogen mass fraction of fuel, average temperature of PEN, current density and activation potential also rise. However, with increasing the delivery rate of air, average temperature of PEN decreases. In particular, it is effective to improve the output voltage by reducing the thickness of anode or increasing its porosity.