The invention provides a refining method of a proton pump inhibitor. The refining method comprises the following steps in sequence: mixing a crude proton pump inhibitor, metallic zinc or nickel catalyst, formate and an alcoholic compound, and heating to react to obtain the proton pump inhibitor. Compared with the refining method for recrystallizing in a physical way in the prior art, the refining method provided by the invention has the following advantages that firstly, the N-oxide impurity in the crude proton pump inhibitor is reduced into corresponding proton pump inhibitor by the chemical method, so that the yield of the proton pump inhibitor is increased, the cost is decreased, and the the environment pollution is reduced; secondly, the alcoholic compound serving as the solvent also can be used for recrystallizing, and therefore, the purity and quality of the proton pump inhibitor are improved; and thirdly, the physical process and the chemical process are carried out at the same time, the operation is simple, and the benefit is provided for industrialization.