The invention relates to a preparation method of 2,2,2-trifluoroethyl-1,1,2,3,3,3-hexafluoroisopropyl ether. Trifluoroethanol reacts with hexafluoropropylene in an organic polar solvent and in the presence of potassium fluoride and phase-transfer catalyst, at the temperature of room temperature to 50 DEG C, so as to produce 2,2,2- trifluoroethyl-1,1,2,3,3,3-hexafluoroisopropyl ether, and the phase-transfer catalyst is 18-crown-6, tetrabutylammonium chloride or trimethylphenylammonium. The preparation method of 2,2,2- trifluoroethyl-1,1,2,3,3,3-hexafluoroisopropyl ether has the advantages of mild reaction conditions, normal pressure reaction, low catalyst price, convenient post-treatment, and good yield and selectivity, and is suitable for industrial production.