A manufacturing method of a proton exchange membrane is provided, which includes the steps as follows. The hydroxyl groups are disposed on the surface of a substrate by a hydrophilic treatment. The hydroxyl groups on the substrate are chemically modified with a coupling agent by a sol-gel process. The substrate is exposed to an amino acid with a phosphonate radical so that the amino acid containing a phosphonate radical can be chemically bonded with the coupling agent. The chemically bonded substrate is immersed in phosphoric acid for absorbing the phosphoric acid. The substrate blended with the phosphoric acid is placed between at least two leak-proof films for the purpose of preventing the leakage of the absorbed phosphoric acid. The proton exchange membrane manufactured by this method enable to retain the phosphoric acid in organic/inorganic complex form and micron/nano complex pore size. |