Method for fabricating a free standing film of colloidal photonic crystal (CPC) has been studied. The CPC films were previously fabricated by drop-coating monodisperse polystyrene nanoparticles on agarose hydrogel. The water-based medium in these CPC films was not long-term stable and the changing of air-humidity resulted in the variation of their optical properties. To sustain the optical properties of CPC film, the gel medium in the film can be replaced by more stable materials with slightly changing the periodic ordered structure of crystalline colloidal array (CCA). In this work, the polystyrene nanoparticles with a diameter of 160 nm were suspended in a nonionic polymerizable monomers solution which composed of N-vinyl pyrrolidone, acrylamide, N,N’ methylene bis acrylamide and benzoin methyl ether. A solid film was formed by shining UV light on the suspension to initiate the polymerization process. From this process, the CCA was fixed into the free standing film. Moreover, the free standing films of CPC were also prepared with various particle concentrations in the suspension in water between 250 to 1000 g/L.The diffraction spectra from these free standing films were measured by optical diffractrometer.The shifting of diffraction peak of free standing photonic crystal film can be described by the decrement of the nanoparticle distance.