Provided is a method for unlocking by use of a knob. The method is applied to an electronic device provided with an operation knob. The method includes the following steps: detecting (1) an action of the operation knob in a screen locked state in real time; and starting (2) an unlocking program in response to rotation of the operation knob: calculating the rotational circumferential distance of the operation knob along the current rotational direction, determining whether the rotational circumferential distance of the operation knob reaches a preset circumferential distance, controlling the electronic device to unlock in response to the rotational circumferential distance of the operation knob reaching the preset circumferential distance, and unlocking failed and returning to step (1) in response to the rotational circumferential distance of the operation knob not reaching the preset circumferential distance.