A liquid crystal display (LCD) including an LCD panel and a back light module is provided. The back light module is disposed below the LCD panel. The back light module includes a planar light source, a reflective polarized light enhancement film, a first prism film and a λ/4 phase retardation film. The planar light source is disposed below the LCD panel, while the reflective polarized light enhancement film is disposed between the LCD panel and the planar light source. The first prism film is disposed between the reflective polarized light enhancement film and the planar light source. Besides, the λ/4 phase retardation film is disposed between the reflective polarized light enhancement film and the first prism film. The back light module has a relatively high light utilization rate, and the LCD has favorable display luminance.