Using a computer, the structure of a grating light valve (GLV) was simulated based on analysis of optics characteristic of a GLV. Driven by the electrostatic force, the GLV has high optical efficiency and high switching speed. These traits were used to design a 1×2 microelectromechanical systems (MEMS) optical switch in order to improve upon the traditional MEMS optical switch’s shortcomings, such as easy wear, slow switching times, and short switching lives. The simulation experiment using CoventorWare shows the firstorder diffraction efficiency achieves 50% and the switching time is at microsecond level when the 1.55 μm light wave length is in normal incidence and the given parameters of GLV are assigned.