The main materials of polymer electrolyte membrane fuel cell (PEMFC) are carbon (C) and Stainless Steel (Fe). The dynamic current of PEMFC will cause nonuniform distribution of current density in these materials. Simple models which materials are carbon (C) and Stainless Steel (Fe) are used in testing. A testing device using electromagnetic method was set up to detect the induced electromotive force in models. Theoretical calculations using electromagnetism and mathematics are set up to calculate the current density distribution of models. It is shown from the comparison between calculated values of the formula and measured values that the dynamic current of PEMFC will cause skin effect.