The present invention discloses an ultra-narrow frame module and a liquid crystal display device. The ultra-narrow frame module comprises a light guide plate, a light incident surface is formed at onesurface of side surfaces of the light guide plate opposite to a light source assembly, at least one side surface in other side surfaces connected to the light incident surface is provided with a groove, the groove is filled with a transparent material whose refractive index is larger than that of the light guide plate. In the invention, the light emitted by the light source assembly is emitted tothe light guide plate through the light incident surface of the light guide plate, due to the reflection effect of the light guide plate, light leakage occurs on other side surfaces connected to thelight incident surface of the light guide plate, and so at least one side surface in the other side surfaces connected to the light incident surface is provided with a groove, if the light in the light guide plate is emitted into the groove in the side surface, since the refractive index of the transparent material filled in the groove is larger than that of the light guide plate, the light emitted into the groove is refracted to the light guide plate again through the groove, the light is deflected and does not leak from the side surface of the light guide plate, and thus a problem of light emission at the side of the light guide plate can be improved by a light guide plate structure.