A reflector for flat panel display device. The device is constructed having two sidewalls and a base wall defining with the sidewalls a receiving chamber having a substantially U-shaped cross section for holding a light source. The sidewalls and the base wall each have a reflecting surface adapted to reflect light from the light source installed in the reflector. The sidewalls each have a protruded flange (block) respectively disposed at an outer side for grounding with a grounding metal frame. The protruded flange (block) of each sidewall is not disposed with the respective sidewall on the same plane.