The present disclosure provides a method for preparing a high cohesive energy adsorbent for fluoride removal, which includes the following steps: S1. adding NaHF2—NiF·6H2O additive to SiCO ceramic powder, and sintering at a temperature of 310-330° C. for 18-22h to obtain a sintered substance; S2. grinding the sintered substance to obtain particles with a size of 2-3 mm, and mixing the particles with polyacrylonitrile to form a composite polymer; and S3. molding the composite polymer by a vacuum baking process at a temperature of 75-85° C., then performing ball milling and sieving to obtain the high cohesive energy adsorbent for fluoride removal. The high cohesive energy adsorbent for fluoride removal may be used in the adsorption and separation of the C2F6—CHF3—CClF3 mixture system, and the contents of CHF3 and CClF3 are lowered to less than 10ppmv.