A mobile robot, including: a body, a drive system for driving the movement of the mobile robot, a light emitter for emitting light towards a detection face, a photoelectric sensor for responding to light coming from an environment and/or light emitted by the light emitter, an adjustable impedance unit connected to the photoelectric sensor, and a controller. The controller adjusts the adjustable impedance unit to form at least two types of gear values with different impedances and responds to, under the condition of each type of gear values, a sampling difference value determined when the light emitter is in a turn-on and a turn-OFF state, so as to prevent the generation of a misjudgment from causing the mobile robot to carry out an accidental action, such that the mobile robot can work in a special working environment with strong light exposure and a black light-absorption detection face.