A liquid crystal display, comprising a liquid crystal display panel, a backlight and an optical film, wherein the liquid crystal display panel is the outmost layer of the liquid crystal display; the backlight comprises a light source, a prism sheet, a diffusion sheet, a light guide plate and a reflective sheet, wherein the prism sheet, the diffusion sheet, the light guide plate and the reflective sheet are arranged under the optical film in sequence, and form a multi-layered structure; and the optical film is provided between the liquid crystal display panel and the backlight and comprises a first optical layer and a second optical layer, wherein the first optical layer is disposed on a side of the second optical layer facing the backlight, and is a prism sheet comprising a plurality of prisms, wherein an apex angle of each prism faces and fits the second optical layer; the second optical layer is a composite material layer comprising a base material and a doping layer in the base material, the liquid crystal display is arranged so that the optical film receives natural light from the backlight which comprises polarized light parallel to the light-passing direction of the optical film and polarized light perpendicular to the light-passing direction of the optical film, the first optical layer and the base material of the second optical layer each have a refractive index in a range from 1.3 to 1.8, an angle of incidence α of the natural light from the backlight at an apex angle (vertex) of each of the plurality of prisms is in a range of 52.2 degrees≤α<90 degrees, and an apex angle (vertex) β satisfies the relation β=180°-2α, and the liquid crystal display is arranged so that polarized light parallel to the light-passing direction of the optical film enters the optical film at Brewster angle and is refracted by the doping layer of the second optical layer, while the light perpendicular to the light-passing direction of the optical film is reflected by the doping layer of the second optical layer for a plurality of times and converted into natural light by the diffusion of each layer (30, 40, 50, 60) of the backlight, which combines with the light produced by the light source to reach the optical film; wherein the doping layer comprises a plurality of elongated bubbles, the doping layer comprises a plurality of layers formed by the plurality of elongated bubbles, and the bubbles further comprise SiO 2 particles. the first optical layer is disposed on a side of the second optical layer facing the backlight, and is a prism sheet comprising a plurality of prisms, wherein an apex angle of each prism faces and fits the second optical layer; the second optical layer is a composite material layer comprising a base material and a doping layer in the base material, the liquid crystal display is arranged so that the optical film receives natural light from the backlight which comprises polarized light parallel to the light-passing direction of the optical film and polarized light perpendicular to the light-passing direction of the optical film, the first optical layer and the base material of the second optical layer each have a refractive index in a range from 1.3 to 1.8, an angle of incidence α of the natural light from the backlight at an apex angle (vertex) of each of the plurality of prisms is in a range of 52.2 degrees≤α<90 degrees, and an apex angle (vertex) β satisfies the relation β=180°-2α, and the liquid crystal display is arranged so that polarized light parallel to the light-passing direction of the optical film enters the optical film at Brewster angle and is refracted by the doping layer of the second optical layer, while the light perpendicular to the light-passing direction of the optical film is reflected by the doping layer of the second optical layer for a plurality of times and converted into natural light by the diffusion of each layer (30, 40, 50, 60) of the backlight, which combines with the light produced by the light source to reach the optical film; wherein the doping layer comprises a plurality of elongated bubbles, the doping layer comprises a plurality of layers formed by the plurality of elongated bubbles, and the bubbles further comprise SiO 2 particles.