We propose a 1×2 optical switch based on electrowetting effect. The proposed optical switch is composed of a black liquid and a clear liquid. The black liquid is placed in the center of the bottom substrate. The surrounding is filled with transparent oil. The bottom substrate is fabricated with three abreast indium tin oxide electrodes. When we apply a voltage to one side of the electrode, the droplet stretches toward the same side of the substrate. When the voltage is removed, the droplet returns to its original state with the aid of interfacial tension and adsorption force. In our experiment, it requires ∼52 and ∼250 ms for the device to switch the light off and on, respectively. The maximum optical attenuation can reach ∼29 dB and the minimum power consumption is 14.9 μW. When we apply a voltage to the both sides of the electrodes, the device can achieve the function of light-on and light-off states simultaneously. The proposed optical switch has potential applications in optical switching networks, variable optical attenuators, and optical routers.