A micro-fuel-cell stack of six cells with an active area of and 2.5 W output power has been designed and fabricated in-house. It can go with mini hydrogen storage and provide enough power for portable electric products. Under polarization curve measurement, when the voltage was scanning to low voltage, the performance was quickly decayed by the low fuel concentration. This result was contributed by a limited fuel supply of metal hydride hydrogen tank. The voltage declined to very low voltage in some of the cell stacks when the current output was at high current. This phenomenon is attributed to the self-breath of air in the cathode. At the higher current of 0.9 A condition, the stack voltage was decreased even though the high hydrogen flow rate was increased. The solution to prevent the decrease in voltage is adding the airflow in the cathode. The fuel cell performances respond to the transient of load changes influenced by the hydrogen flow rate and step increase in current. The flow change can decrease the high resistance in the transient of the current output, which prevents membrane electrode assembly (MEA) degradation caused by being operated for many times. After a series of experiments in this study, the micro-fuel-cell system demonstrates the ability of offering a stable power to a cell phone or robot with reliability.