An electronic device capable of controlling light-emitting diode (LED) bright is provided. The electronic device includes a signal producing unit for producing an operation signal; a Micro Control Unit (MCU) configured for outputting a normal brightness control signal according to the operation signal, and outputting a ultra brightness control signal according to the operation signal when an actual idle time of the electronic device reaches or exceeds a predetermined idle time; a pulse current control unit for controlling an output current according to the normal brightness control and the ultra brightness control signal; and a LED illuminator array for emitting light based on the output current. The MCU terminates the output of the ultra brightness control signal when an actual time of outputting the ultra brightness control signals reaches a predetermined time, and then the LED illuminator array resumes its normally bright. A control method is also provided.