A kind of flexible cantilever beam electromagnetic optical switch which is used in the wave length channel selection system was designed and fabricated. It was manufactured by micro-opto-electromechanical system technology and composed of a plane circular coil in flexible polyimide cantilever beam, a cylindrical permanent magnet，the substrate and a reflector prism with two reflecting surfaces. The switch′s motion depends on the current direction in the coils. The simulation of force between the coils and the permanent magnet was proceeded by finite element method. In the same way, the relationship between cantilever’s deflection and restoring force, and electromagnetic force were obtained. The switch′s actuation performance was tested and the results indicate that deflection of the cantilever is 0925 mm with 015 A current input，which satisfies the need of the wave length channel selection system of changing the propagation direction of the optical beam.