The present invention relates to an ion exchange membrane and a manufacturing method therefor and, more specifically, to an ion exchange membrane comprising a cross-linked sulfonated triblock copolymer and carbon nanotube, which is utilizable in a redox flow energy storage device, etc. due to high ion conductivity, mechanical strength and ion selectivity. The ion exchange membrane of the present invention has superior ion selectivity and mechanical strength and thus can greatly improve the performance of a fuel battery, etc. when applied thereto.