Abstract: The characteristics of foamed metal electrodes are investigated to study electric potential distribution in electrolytes on foamed metal cathodes and the mathematical models are proposed.The equations of macro-reaction rates and the changes of reaction rates with electrolysis time are obtained.The electrolytic reduction of Fe(CN) ^3- ₆ on foamed metal cathodes is studied and the electric potential distribution in the electrolytes on foamed nickel and foamed copper cathodes is measured.The effects of concentration, flow rate, conductance of electrolyte,cell voltage,cathode dimension on potential distribution are studied. The results show that the potential distribution tends to be uniform with decreasing cell voltage and decreasing flow rate and with increasing conductance of the electrolyte. As the thickness of the cathode ( x₀) is fixed,potential distribution in the radial x -direction tends to be uniform with increasing height,of the cathode.As the height of the cathode is fixed,potential distribution in the flow direction ( y -direction) of the electrolyte is tends to be uniform with increasing thickness of the cathode.The general potential drop at the inlet is almost directly proportional to x 2 0,and at the separator membrane location potential distribution in the y -direction is least of all uniform.As x is fixed, the potentical distribution in the y -direction is nearly an exponential function of y .The results show that the mathematical models are validated by the experiments .