A method and a system for fabricating a liquid crystal film are proposed. First of all, mechanical rubbing is performed on a surface of a plastic substrate. The surface of the substrate is applied with dispersed liquid crystal material over the substrate. At least one cycle annealing treatment is performed to orientate liquid crystal molecules in a fixed direction, so that a liquid crystal solid film is formed by curing the liquid crystal molecules. In addition, a method for fabricating a brightening film using the liquid crystal solid film is also proposed. The method is applicable to a continuous process for forming a cholesteric liquid crystal film on the plastic substrate, and fabricating a reflective cholesteric liquid crystal brightening film using the cholesteric liquid crystal film, so that light transmittivity and intensity are effectively increased under the same backlight source.