The utility model discloses an improving the hanging down of panorama optical devices of eliminating the bireflectance and hanging cover and panorama optical devices, wherein panorama optical devices's quadratic surface reflector can have roughly circular cone shape, and this shape is basal portion to top taper off leniently, the top includes the aperture. Panorama optical devices still includes speculum and one or more optical components's combination, the speculum can be fixed a position in the cover is hanged to hanging down of optical devices, be located with the circular cross section of toper shape parallel plane roughly. The speculum can be with the environment light reflex by quadratic surface speculum reflection to the aperture in, on perhaps will be from the light reflex of aperture transmission to the quadratic surface reflector. The outstanding cover that hangs down can have roughly circular cone shape, and the aperture is arrived twice and the secondary reflection of production by environment light to its elimination, the utility model discloses can utilize the outstanding cover that hangs down to reduce or to eliminate the stripe in order to absorb secondary reflection.