NOVELTY - The method involves supplying hydrogen at 70 degrees C to a cathode of a degraded fuel cell stack for one hour, and then storing the fuel cell stack for two to three days. An oxide formed on the surface of a platinum catalyst of the cathode is removed by storing the fuel cell stack, such that mobile platinum ions is combined with electrons and re-precipitated as highly active platinum.The removal of oxide from the surface of the cathode supplied with hydrogen, is repeated to partially recover the performance of the fuel cell stack.    USE - Method for recovering performance of degraded polymer electrolyte fuel cell of degraded fuel cell stack. Can also be used in motor vehicles such as passenger cars, sports utility vehicles (SUV), buses, trucks, commercial vehicles, watercraft such as boats and ships, aircraft, hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, fuel vehicles, or gasoline-powered and electric-powered vehicles.    ADVANTAGE - The performance of the degraded polymer electrolyte fuel cell is partially recovered. The catalytic properties of the cathode is recovered in a reusable state by supplying hydrogen to the cathode of the degraded fuel cell stack for the predetermined period of time. The active site of the metallic catalyst having high catalytic activity is increased to reduce the active resistance of the electrode and increase the power output per unit cell. The cathode potential is reduced to the standard hydrogen electrode (SHE) potential, and the reduction of oxides on the platinum surface is facilitated. The electrochemical reduction reaction is facilitated in a hydrogen reduction atmosphere. The degraded fuel cell stack is reused, and the durability of the fuel cell stack is improved.    DESCRIPTION OF DRAWING(S) - The drawing shows a graphical representation illustrating the relationship between current-voltage characteristics of fuel cell stack. (Drawing includes non-English language text)