This paper proposes a new chemical mechanical polishing (CMP) process method for CaF<sub>2</sub> single crystal to get ultraprecision surface. The CMP processes are improving polishing pad and using alkaline SiO<sub>2</sub> polishing slurry with PH=8, PH=11 two phases to polish, respectively, and the roughness can be 0.181nm Rq (10μm×10μm). The CMP process can’t get high surface figure, so we use ion beam figuring (IBF) technology to obtain high surface figure. However, IBF is difficult to improve the CaF<sub>2</sub> surface roughness. We optimize IBF process to improve surface figure and keep good surface roughness too. Different IBF incident ion energy from 400ev to 800ev does not affect on the surface roughness obviously but the depth of material removal is reverse. CaF<sub>2</sub> single crystal can get high precision surface figure (RMS=2.251nm) and still keep ultra-smooth surface (Rq=0.207nm) by IBF when removal depth is less than 200nm. The researches above provide important information for CaF<sub>2</sub> single crystal to realize ultra-precision manufacture.