An ion exchange resin and a method for preparing the same are provided. An ion exchange resin is formed by a composition, and the composition includes a crosslinking agent and an ionic compound with sulfonate ions. The ionic compound with sulfonate ions is formed by reacting an epoxy resin with an ionic monomer with sulfonate ions or an ionic polymer having sulfonate ions. The ionic monomer and the ionic polymer each has a hydroxyl group or an acid group at the ends. The ionic monomer or the ionic polymer is 40 to 80 parts by weight, and the epoxy resin is 15 to 25 parts by weight, based on 100 parts by weight of the ion exchange resin. An ion exchange resin with a network structure is formed after the ionic compound with sulfonate ions reacts with the crosslinking agent.