Physical method, including thermal evaporation and magnetic sputtering, and chemical coating method are applied to prepare organic-inorganic composite chromotropic film. The chromotropic film showing obvious opto-chromo effect with the change of incidence angle and view angle, can be used as a counterfeiting preventing material. The structure of the film system is designed as PET/Cr/dielectric/Al according to the optical interference principle of multiplayer. The dielectric materials are polymer and SiO2 respectively. The SiO2 prepared by sol-gel method shows nano-holes. Its refractive index is between 1.15 and 1.45 by varying the method and condition of catalyst and gel process. Fabrication method and film characteristics are described.