A brightness feedback display device includes a LCD panel, a plurality of first photo-sensors for sensing the environmental brightness variation of the display device itself. Corresponding sensing signals are delivered to first converters for being converted to first digital reference signals that are delivered to a microprocessor, thereby determining how much brightness of the display panel increases or decreases. Via a light-guiding element and a second photo-sensor installed within the display panel, the light brightness from the display panel is sensed and converted to a second digital reference signal that is compared with the first digital reference signals to determine whether the display brightness is at an optimal value.