A novelmethod of fabricating light guide stick with sub-micron Gratings is proposed. By using rigorous cou-pled-wave theory, the relationship between transmission efficiency and dep ths of grooves is analyzed. The light-guid-ing properties of sub-micron gratings have been studied based on the linear part of the relationship curves. The light guiding unit on the surface is composed of sub-micron gratings whose transmission wavelengths are red, green and blue in order. The light sources are red, blue and green LED. The transmission angle is controlled by grating fre- quency and the diffraction efficiency is controlled by groove depth of sub-micro gratings to get uniformity of transmission filed.