The experimental research for micro-electro-mechanical system (MEMS)-based grating moving light modulator (GMLM) is important for its further applications. Interference optical signal processing system with GMLM module was carried on, with He-Ne laser as light source, filter placed on the frequency spectrum plane, and microscope and CCD placed on the imaging plane and used for magnifying and recording imaging. The laser beam from He-Ne laser was incident on the GMLM as parallel light after passing a beam expander and a collimating lens, the GMLM is placed on the input plane of the interference optical signal processing system and the result is consistent to theoretical result. The optimization of GMLM model was achieved, the grating frame and cantilevers are processed as non-reflective, and as a result the total reflective surface composed of the movable grating and the nether mirror is integer multiple of grating period. The optimized model was theoretically analyzed in details by scalar diffraction theory, with optical efficiency of 81.06%, filling factor of 74.67% and contrast ratio higher than 5000∶1 in the condition of grating period of 8 μm, duty ratio of 0.5,grating frame of 2 μm, and period number of 6.