Method for preparing fluticasone furoate (6α,9α-difluoro-11β-hydroxy-16α-methyl-17α-[(2-furoyl)oxy]-3-oxo-androsta-1,4-diene-17β-carbothioic acid S-fluoromethyl ester) by directly subjecting a compound of Formula III and a complex of a fluoromethylating reagent in presence of an organic base to a replacement reaction to obtain the target compound. Generation of impurities in a process via Compound IV is avoided; the method is simple with mild reaction conditions, suitable for industrial production, and yields products with purity of 98% by HPLC.