A gesture recognition module for recognizing a gesture of a user, includes a detecting unit, including at least one image capture device, for capturing at least one image of a hand of the user, to obtain a first position and a second position of the hand sequentially; a computing unit, electrically coupled to the detecting unit, for determining a first angle between a first virtual straight line connected between a fixed reference point and the first position and a reference plane passing through the fixed reference point, and determining a second angle between a second virtual straight line connected between the fixed reference point and the second position and the reference plane; and a determining unit, electrically coupled to the computing unit, for determining a relation between the first angle and the second angle, to decide whether a gesture of the hand is a back-and-forth gesture.