A provided simple method for preparing an AgxBiOy visible-light responsive catalyst comprises the following steps: A, at room temperature, respectively getting Bi2O3 and Ag2O, and preparing reactants according to the molar ratio of 1:1-7; B, grinding in a mortar for 0.5 h; C, transferring the ground powder into a culture dish, putting in a saturated water vapor environment at room temperature, and reacting for 24 h; and D, taking out the sample, and drying at 60 DEG C for 12 h, so as to obtain AgxBiOy, wherein x=3 or x=5, y=3 or y=5. The innovation point is that controllable preparation of the silver bismuthate is realized, in other words, the sample composition is controlled by changing the Bi/Ag ratio, and operation uneasiness and time consumption and energy consumption in a conventional preparation method are overcome. The reactants Bi2O3 and Ag2O are both obtained through market purchase, and the preparation method is simple, carbon discharge in the product production process is reduced, and the preparation method is suitable for large-scale industrialized production application.