When CaF2 materials are used in projection lenses, the performance of the projection lenses can be improved greatly. This paper researches the process of CaF2 crystal fabrication to realize its high precision optical fabrication in all wave bands. Firstly, the pitch lap and the diamond powder were used to get a relative better figure and surface quality of a CaF2 element. Then, the technological parameters of the polishing lap, such as rotation speed, movement range and pressure were optimized, and the colloidal silica was used in polishing to reduce the high frequency errors in the CaF2 element, remove the scratch in machining and to obtain a smaller mid-spatial error and smaller higher frequency roughness. Finally, the ion beam figuring technique was used to repair finely the surface figure of the element meanwhile maintaining the high frequency error in the CaF2 element. The Experiments were conduct on a CaF2 crystal plane with a diameter of 100 mm, and the results indicate that its 37 Zernike fit error and the Zernike residual error reach to 0.39 nm RMS and 0.43 nm RMS, respectively, and the roughness reaches to 0.31 nm on average. These results satisfy the nanometer machining requirements of the projection lens, and lay a basis for development of the high performance projection lenses.