The purification method of the alkylene glycol

A method for purifying alkylene glycol containing a nitrogen compound contained in a dye as an impurity is provided. In purifying alkylene glycol containing nitrogen compounds contained in a dye as impurities, the alkylene glycol is subjected to an oxidation treatment operation using an oxidizing agent by ozone and a distillation operation. This can be achieved by a purification method. [Selection figure] None