Trifluoromethyl steroids 1a, b; 2a, b; 3a, b have been synthesized by starring from Delta(5(10))-estren-3, 17-dicarbonyl-3, 3-dimethyl ether (4) and dl-18-methyl-Delta(2(3),5(10))-estra-diene-17-carbonyl-3-methyl ether (5), and by using trimthyltrifluoromethylsilane as the trifluoromethylating agent under the catalysis of tetramethylammonium fluoride. The overall yields were 82%, 76%; 54%, 62%; and 27%, 25%, respectively. The alpha-configuration of trifluoromethyl group of 17-position was determined by X-ray crystal diffraction method. Compounds la, 2a and 3a showed high affinity for rat uterus PRc. The test of biological activities of compounds Ib, 2b and 3b is proceeding.