An electronic device is provided. The electronic device includes a first processor, a power supplier, and a controller. A power supplier storing electricity provides power to the electronic device. The controller detects remaining electricity quantity of the power supplier and determines whether the current remaining electricity quantity is larger than an electricity-quantity threshold. When the controller determines that the current remaining electricity quantity is not larger than the electricity-quantity threshold, the controller activates a frequency control operation to control an operation frequency of the first processor.