The invention discloses an optical device for converging and diverging X-ray, which is used for realizing the low-energy X-ray filtering and the high-energy X-ray converging and diverging. The optical device comprises a solid element made of glass material, and the solid component adopts an ellipsoid platform; a metal film is plated on the side wall of the solid component; one end of the solid component is used for receiving X-ray, and the other end is used for outputting X-ray; a reflecting plane is formed on the critical plane between the glass material and the metal film, and the reflecting plane is used for the X-ray to be reflected when the X-ray is transmitted to the reflecting plane in the solid element and to be converged outside the other end.