The invention provides a display device. The display device comprises a display panel. The display panel comprises an array substrate, a cassette substrate and a liquid crystal layer located between the array substrate and the cassette substrate. The liquid crystal layer comprises nematic phase liquid crystals and a polymer network formed by polymerizable liquid crystal monomers. The refractive index of the array substrate and the refractive index of the cassette substrate are both smaller than the refractive index of the liquid crystal layer. The display device further comprises a light emitting module and a light modulating element. The light emitting module is used for emitting light to the light modulating element. The light modulating element is used for modulating received light so that modulated light can be transmitted into the liquid crystal layer from the side surface of the display panel; besides, the included angle between the direction of the light transmitted into the liquid crystal layer and the thickness direction of the display panel is larger than the total reflection critical angle generated when the light is transmitted to the array substrate or the cassette substrate from the liquid crystal layer. Correspondingly, the invention further provides a making method of the display device. According to the display device and the making method thereof, the contrast ratio of the display device can be increased.