One of the most challenging problems in SOFC is the thermal compatibility of materials. Mechanical failure, or cathode delamination induced performance degradation, is related to local heat generations. An accurate measurement of spatial temperature distribution with correlated electric current provides good information for fuel cell performance and thermal management. Because insufficient ability of measuring electric current introduced heat generation, infrared thermography, instead of thermocouple, was used to measure the instantaneous cathode surface temperature response to the electric current in an operating electrolyte supported planar solid oxide fuel cell (LSCF-6ScSZ-NiO). The numerical model was built to study the coupled current and temperature relation by incorporating the temperature dependent material properties, i.e., Ohmic resistance and activation resistance, as a global function in the model. The thermal and electric fields were solved simultaneously. The measured and the predicted results agreed to each other well. The cathode polarization overpotential tended to increase with the current at the low current densities, but the simulated polarization-current curve exhibited a decreased slope under higher current densities that is ascribed to the local temperature increases due to the current.