A broadband cholesteric liquid crystal film, which is a single-layer liquid crystal material structure and has a top surface and a bottom surface, wherein the broadband cholesteric liquid crystal film consists of a first region, a second region, and a third region, and the first region is adjacent to the top surface of the cholesteric liquid crystal film, the third region is adjacent to the bottom surface of the cholesteric liquid crystal film, and the second region is located between the first and third regions, and the average helical pitch P1 of the first region and the average helical pitch P3 of the third region are both larger than the average helical pitch P2 of the second region.