An electronic device including a power switch, a switch unit, a power supply unit and a control unit is provided. Two power ends of the power switch are connected in parallel with two connecting terminals of the switch unit. The power supply unit generates a system voltage by a power come from the power switch or the switch unit. When the two power ends of the power switch are conducted for a predetermined time, the power is provided to the power supply unit and the electronic device starts up. Furthermore, the control unit controls the switch unit to conduct the two connecting terminals, so that the power is still provided to the power supply unit through the switch unit after the two power ends are disconnected. When the electronic device is shut down, the control unit controls the switch unit to disconnect the two connecting terminals.