Method for refining sugammadex sodium

The invention discloses a method for re-crystallizing, refining and purifying sugammadex sodium. The method comprises the following steps: adding a protective agent to crude sugammadex sodium, and performing re-crystallizing under the protection of an inert gas to obtain pure sugammadex sodium, wherein the protective agent is selected from one or a mixture of two or more of mercaptoethanol, mercaptoacetate, mercaptoacetate ester, mercaptopropionate, mercaptopropionate ester, glutathione, cysteine, cystamine, dithioerythritol, dithiothreitol, trisubstituted organophosphorus compounds and trisubstituted organophosphorus compound salts. The method has the advantages of simplicity in operation, high product purity, good economy, and suitableness for industrial production.