Cellulose nanocrystals (CNC) are prepared by hydrolysis of cellulose catalyzed by sulfuric acid. According to the source and hydrolysis conditions of cellulose, the diameter of the nanocrystals is about 5~15 nm and the length is about 100~300 nm.CNC organizes into chiral nematic liquid crystals in water. When dried into a thin solid film, the CNCs retain the helicoidal chiral nematic order and assemble into a layered structure. In the process of CNC self-assembly, it is possible to add sol-gel precursors, such as Si(OMe)₄. With the evaporation of solvent, these precursors undergo hydrolysis and condensation, leading to a chiral nematic silica/CNC composite material.In addition, porous, rainbow colored organic silica or titanium dioxide films are also obtained using this methods. These thin films can be used as filters, reflectors, and membranes. The most important thing is that the synthesized chiral mesoporous silica can be used as a chiral chromatographic stationary phase material to separate chiral drugs. The results shows that the effect of chiral separation is remarkable, providing a new method for the development of chiral new materials based on CNC.