The present invention provides a cell or stack for evaluating the performance of a fuel cell and a method of evaluating the performance of the fuel cell using the cell or stack, in which a semiconductor thermoelectric device, attached to the side surface of the unit cell or stack of the fuel cell, is provided maintain the cell or stack at a uniform temperature. The temperatures of an anode and a cathode of the fuel cell can be precisely changed or maintained such that the performance of the fuel cell can also be measured in sub-zero temperature conditions without requiring a separate environmental chamber. A rate of temperature decrease, at which the temperature decreases to a certain sub-zero temperature, or a rate of temperature increase can be precisely controlled.