The invention discloses a method for purifying sugammadex sodium. The method is characterized in that a sugammadex sodium crude product is subjected to dissociation in an organic acid-organic alkali-reducing agent mixture system into sugammadex acid, the free condition is mild, the product stability is high, and the purification effect of the sugammadex acid is better, and after further recrystallization purification and salt formation, the high-purity sugammadex sodium can be obtained. Both the dissociation and recrystallization steps of the purification method introduce a reducing agent so that the reaction system has oxidation resistance, and effectively controls the formation of oxidized impurities, the reagent is easy to obtain, and the operation is simple and safe, compared with theprior art, a large amount of activated carbon, multitime long-time dialysis and preparation of HPLC are employed, the sugammadex sodium is purified, the method is more suitable for industrial amplification, and provides bulk drugs of sugammadex sodium which can meet the purity requirements and impurity limitation for preparation production. The invention further discloses high-purity sugammadex sodium with content being more than 99.5% and single impurity of less than 0.1%, and a preparation and use thereof.