A liquid crystal display panel and a liquid crystal display (LCD) device are discussed. One monochromatic light is transmitted through a liquid crystal layer and converted into white light having a plurality of wavelengths through upper photo conversion layer, thus improving light transmittance of liquid crystal and reducing a change in a screen color. The liquid crystal display panel includes: first substrate over the backlight unit; a liquid crystal layer over the first substrate to transmit the one monochromatic light; a photo conversion layer over the liquid crystal layer for converting the one monochromatic light into white light; a color filter layer over the photo conversion layer for filtering the converted white light to display color; and a second substrate on the color filter layer.