A dividing wall distillation column for producing high-purity n-butanol and a method for the production of high-purity n-butanol by fractional distillation are disclosed. More particularly, the method which provides a dividing wall distillation column with crude n-butanol as a feed to perform a fractional distillation of n-butanol and an apparatus thereof are disclosed. The dividing wall distillation column exhibits the effects of a two distillation column from only one distillation column, thereby reducing energy and the costs of installing the apparatus as compared to conventional distillation systems.