The invention discloses a preparation method of Bi3O4Br single crystal nano-ring photocatalytic material in a square hole-shaped structure. Soluble bismuth salt and bromine-containing compound are used as main raw materials, two surfactants are used for regulation and the Bi3O4Br single crystal nano-ring photocatalytic material in a square hole-shaped structure is prepared by a solvothermal method. The microscopic structure of the synthesized Bi3O4Br single crystal nano-ring in a square hole-shaped structure which is displayed by scanning electron microscope photograph is a relatively regular square hole-shaped structure which is formed by stacking several layers of Bi3O4Br sheets. The Bi3O4Br single crystal nano-ring photocatalytic material in a square hole-shaped structure can well absorb visible light and shows high photocatalytic activity in the experiments of simulating visible light to produce oxygen, degrade salicylic acid and methyl orange. The method for synthesizing the Bi3O4Br single crystal nano-ring photocatalytic material in a square hole-shaped structure is simple, is mild in synthesis condition and is beneficial to large-scale industrial production.