The invention belongs to the technical field of fuel cells, and provides a hydroxide ion exchange membrane for preparing hydrogen for fuel cells and a preparation method thereof. The method comprisescoupling a N-vinylimidazole with methyl iodide to alkylate N-vinylimidazole, copolymerization of styrene and acrylonitrile under ultrasonic vibration, crosslinking reaction with alkylated imidazole, and replacement of iodine with hydroxyl by sodium hydroxide. Compared with the traditional method, the prepared hydroxide ion exchange membrane of the present invention, At that same time, the raw material is environmentally friendly and pollution-free, the membrane can be directly synthesize at one time without subsequent membrane formation, the preparation process is simple, the conductivity andthe mechanical property are easy to control, and the membrane is suitable for large-scale industrial production. The invention has excellent hydrophilicity and the anion transmission rate, and remarkably improves the alkali tolerance and stability of the membrane material, and the raw material is environmentally friendly and pollution-free, and the membrane can be directly synthesized at one time.