A microstructural polarized light-guide device comprises an unpolarized light source module, a subwavelength polarization beam splitter structure and a polarization conversion module, the unpolarized light source module comprises a light-guide plate and a light source at the edge of the light-guide plate, the material of the light-guide plate is PMMA with the characteristic of high transparency, the surface of the light-guide plate has a plurality of extraction patterns, the polarization beam splitter structure is a nano-scale structure and comprises a dielectric nanograting layer and a metallic nanograting layer, and the dielectric nanograting layer and the metallic nanograting layer are vertically stacked with each other, the dielectric nanograting layer is integrated with a surface opposite to the surface with the plurality of extraction patterns, the polarization conversion module is disposed on the surface with the plurality of extraction patterns of the light-guide plate.