A method and device for preparing platinum catalyst are disclosed. The method comprises providing a carbon-based material; immersing the carbon-based material with a platinum precursor solution in a first container; controlling pressure and temperature within the first container to a predetermined temperature and predetermined pressure to form water vapor, and then allowing the water vapor to escape from the first container through a first opening of the first container to a second container; and maintaining the predetermined temperature and predetermined pressure within the first container for a period of time to reduce the catalyst on the carbon-based material. |