The invention discloses a combined X-ray optical element used for converting a high-energy divergent X-ray beam into a parallel X-ray beam or converging the high-energy divergent X-ray beam into one point and filtering low-energy X-ray. The optical element has an axis symmetric structure and an outline bus in the axial direction meets a quadratic curve equation; the optical element comprises a plurality of solid components by which X-ray is transmitted; the solid components are made of glass material and plated with metal films on the lateral walls; a critical surfaces of the glass material and the metal films form reflecting surfaces for reflecting X-ray when the X-ray passes by the reflecting surfaces; one end of each solid component is used for receiving the X-ray and the other end is used for outputting the X-ray.