The invention discloses a catalyst as well as a preparation method and an application thereof in synthesis of trifluoroiodomethane and pentafluoroethyliodide. The catalyst takes one or more of alkali metal salt, alkali earth metal salt, transition metal salt and rare earth metal salt as an active ingredient, the active ingredient is mixed with porous metal fluoride or metal fluoride powder and a proper quantity of adhesives, and the catalyst is prepared in an extrusion forming manner. The catalyst is used for gas-phase synthesis of trifluoroiodomethane and pentafluoroethyliodide after being dried and calcined and has the advantages of stable catalytic activity, long service life and the like.