The invention discloses a novel quantum dot liquid crystal backlight source which comprises a blue LED lamp band, a fluorescent membrane containing green quantum dots and a light guide plate. The fluorescent membrane and the light guide plate are arranged in a stacked mode, the blue LED lamp band is arranged on one or more side edge of the light guide plate, and the surface of the side, facing the light guide plate, of the blue LED lamp band is encapsulated with a red fluorescent layer. The red fluorescent layer is formed by dissolving a red fluorescent material into a tackifier and then applying the material to the surface of the blue LED lamp band, wherein the red fluorescent material is one or a mixture of red light-emitting II-VI and III-V quantum dots, perovskite quantum dots, fluosilicate fluorescent powder, fluotitanate fluorescent powder and nitric oxide fluorescent powder. Compared with the prior art, the liquid crystal backlight source has the advantages that the condition that green light emitted by the green quantum dots is absorbed by red quantum dots or other red fluorescent materials is avoided, the surface of the blue LED is directly encapsulated with the red fluorescent layer, therefore, green light losses can be avoided, and the overall brightness of a white light source is improved by 5%-10%.