A fuel cell system and method for driving the same is disclosed. In one embodiment, the fuel cell system includes i) a fuel supply unit, ii) a fuel cell stack in fluid communication with the fuel supply unit, wherein the fuel cell stack has a fuel inlet and a fuel outlet and iii) a bypass pipe configured to transfer fuel received from the fuel supply unit to a fuel outflow pipe connected to the fuel outlet. In one embodiment, the driving method includes i) receiving fuel from a fuel supply unit, ii) transferring the received fuel to a fuel outflow pipe connected to a fuel outlet of a fuel cell stack and iii) discharging non-reacted fuel from a fuel inlet of the fuel cell stack.