This paper presents the design, fabrication and characterization of grating light valve (GLV) by bulk micromachining process in application of optical modulator. Two kinds of GLVs are designed. The difference between the two GLVs is that the beams which connect the ribbons and the fixed frame are designed in different structure. One is linear cantilever beams and the other is serpentine beams. According to the finite element analysis, at the same driving voltage, the ribbons with serpentine beams obtain a larger displacement Also this kind of ribbons could easily be drop-down and had a flatter bottom which was in favor of improving the diffraction efficiency. The modulation function of GLVs was demonstrated and the modulated light was record. The result showed that the signal which modulated by GLV with linear cantilever beams got a 0.132V peak to peak value, a 29.3μs turn-on responding time, and 10.8μs turn-off responding time. The signal which modulated by GLV with serpentine beams got a 0.558V peak to peak value, a 22.3μs turn-on responding time, and 17.2μs turn-off responding time.