This invention provides an anode plate structure for a flat panel light source of field emission. The structure for the flat panel light source includes an anode plate structure in addition to a known cathode plate structure. The anode plate structure comprises an anode plate and a fluorescent layer formed on the anode plate. The flat panel light source utilizes a cubic-bump structure of the fluorescent layer or a rough surface of the anode plate to increase the lighting areas per unit volume, thereby enhancing the lighting effect of the light source. In the embodiments of the flat panel light source, the rough surface of the anode plate may be formed with a plurality of cubic-bumps, or have a shape of plural concave lenses.