NOVELTY - Producing high-purity esomeprazole sodium, comprises (a) mixing and dissolving 5-methoxy-2-(4-methoxy-3,5-dimethyl-2-pyridyl)methyl sulfo-1H-benzimidazole and solvent, (b) adding water, D-diethyl tartrate and titanium isopropoxide to the 5-methoxy- 2-(4-methoxy-3,5-dimethyl-2-pyridyl)methyl sulfo-1H-benzimidazole and stirring, (c) adding inorganic alkali to the reaction solution, adding dimethylbenzyl hydroperoxide, and stirring, (d) adding alkylphenol to the reaction solution, stirring, filtering, post-processing the filtrate to obtain esomeprazole and salifying.    USE - The method is useful for producing high-purity esomeprazole sodium.    ADVANTAGE - The method: utilizes inorganic alkali, thus it is cost efficient and does not cause environmental pollution; is carried out in a simple manner with short reaction time to produce high-purity esomeprazole sodium; and is easy for post-treatment, repeatability and industrial production.    DETAILED DESCRIPTION - Producing high-purity esomeprazole sodium, comprises (a) mixing and dissolving 5-methoxy-2-(4-methoxy-3,5-dimethyl-2-pyridyl)methyl sulfo-1H-benzimidazole and solvent, where the organic solvent is ethyl acetate or methylbenzene, the weight ratio of the 5-methoxy-2-(4-methoxy-3,5-dimethyl-2- pyridyl)methyl sulfo-1H-benzimidazole to organic solvent is 1:(3-20), (b) adding water, D-diethyl tartrate and titanium isopropoxide to the 5-methoxy- 2-(4-methoxy-3,5-dimethyl-2-pyridyl)methyl sulfo-1H-benzimidazole and stirring for 0.5-2 hours at 20-60 degrees C, where the molar ratio of 5-methoxy-2-(4-methoxy-3,5-dimethyl-2-pyridyl)methyl sulfo-1H-benzimidazole to water is 1:(0.05-0.3), the molar ratio of the 5-methoxy-2-(4-methoxy-3,5-dimethyl-2- pyridyl)methyl sulfo-1H-benzimidazole to D-diethyl tartrate is 1:(0.5-2), and the molar ratio of the D-diethyl tartrate to titanium isopropoxide is 2:1, (c) adding inorganic alkali to the reaction solution, adding dimethylbenzyl hydroperoxide at 10-30 degrees C, and stirring until 5-methoxy-2-(4-methoxy-3,5-dimethyl-2-pyridyl)methyl sulfo-1H-benzimidazole is completely reacted, where the inorganic alkali is potassium carbonate, sodium carbonate, sodium hydroxide or potassium hydroxide, the molar ratio of 5-methoxy-2-(4-methoxy-3,5-dimethyl-2-pyridyl)methyl sulfo-1H-benzimidazole to inorganic alkali is 1:(0.01-1), and the molar ratio of 5-methoxy-2-(4-methoxy-3,5-dimethyl-2-pyridyl)methyl sulfo-1H-benzimidazole to dimethylbenzyl hydroperoxide is 1:(0.95-1.2), (d) adding alkylphenol to the reaction solution, stirring for 5-30 minutes, filtering insoluble matters, post-processing the filtrate to obtain esomeprazole and salifying to obtain high-purity esomeprazole sodium, where the weight ratio of alkylphenol to5-methoxy-2-(4-methoxy-3,5-dimethyl-2-pyridyl)methyl sulfo-1H-benzimidazole is (0.5-3):1, and the added alkylphenol is methanol or ethanol.