An electronic device and an external power supply device control method applicable to the electronic device are disclosed. The electronic device is electrically connected to an external power supply device that is able to switch between an ON state and an OFF state. The electronic device includes a switch module and an internal power module. The switch module, when being triggered, generates a switch signal. The internal power module receives the switch signal and accordingly generates a trigger signal to the external power supply device, so that the external power supply device is triggered to switch from the OFF state to the ON state and accordingly supplies electric power to the electronic device.