A compact see-through video glass optical system based on cascaded waveguide combiner is designed. This optical system is composed of cascaded waveguide combiner, illumination system and eyepiece system. Cascaded waveguide combiner is a new configuration, having an angle selecting film. It can eliminate the ghost images of the semitransparent waveguide. Illumination system for LCOS achieves 92.3% uniformity. Considering modulation transfer function, spot diagram, field curvature, distortion and lateral color, eyepiece system is analyzed. The parameters of the see-through video glasses are listed as follows: LCOS microdisplay resolution: 825 pixel×480 pixel, the total weight of optical system: 135 g. Within a 20 mm exit pupil distance and 8 mm ×8 mm eye motion box, system can achieve 30° field of view, under the drive circuit power consumption of 1 W, the brightness is 3000nit.