An ultra-thin backlight display panel has an upper housing, a lower housing, and a backlight module. Each of the two housings has a cold cathode fluorescent lamp (CCFL) for generating light. The backlight module has a light guide plate, a transparent film, and a reflection film. The light guide plate has four sides, where two of the four sides are connected with the upper housing and the lower housing, and the other two sides are respectively covered with a reflective material. The transparent film is positioned on a first plane of the light guide plate, and the reflection film is positioned on a second plane of the light guide plate to reflect light from the two cold cathode fluorescent lamps.