The invention discloses a potassium ferrate-photo catalytic oxidation method and a device, which comprises that the potassium ferrate is combined with light generated in a photo catalysis reaction to generate Fe (V), and inhibits the recombination of photoproduction electrons and photoproduction cavities in the photo catalytic oxidation; and the reaction device is a potassium ferrate-photo catalytic oxidation reaction device. The method and the device of the invention are not only energy-saving and environment-friendly, but also have extremely high oxidation efficiency and overcome the defects of the high selectivity of a single potassium ferrate oxidation method and the low efficiency of a single photo catalytic oxidation method, and especially overcome the defect of slow reaction time of the photo catalytic oxidation method. In addition, the device of the invention has small volume, simple installation, no noise, wide applicable pH range, and moreover, the device has no secondary pollution, and high reaction rate, thus being a novel experimental device which is integrated with such strong abilities as sterilization, algae removal, oxidation, adsorption, flocculation, muddy removal, decoloration and deodorization, especially being suitable for an application in drinking water treatment.