This paper presents a multifunction reflector controlled by liquid piston for optical switch and beam steering. The multifunction reflector consists of two liquid cavities that are designed with microchannels. Two holes covered with elastic membranes are fabricated on the upper surface of the liquid cavities. When the liquid cavity is injected with liquid, the shape of the elastic membrane changes to form a liquid piston in the position of the holes accordingly. The magnetic base covered with a reflector is fixed on the surface. We can adjust the active number and height of the liquid pistons to drive the reflector deflecting to different directions. Our experiments show that the multifunction reflector can realize the function of 2×2 optical switch. It can also deflect the light beam through an angle of 0°∼72° in two directions. The multifunction reflector has potential applications of free-space optical communications, laser detections and variable optical attenuators.