The invention discloses a low-temperature two-step method for preparing a composite anatase type titanium dioxide visible light catalyst, and belongs to the visible light catalyst. The preparation method comprises the following steps of: 1, adding titanium-containing precursor into alcohol, uniformly mixing and then adding a dopant, fully stirring, then adding an inhibitor and de-ionized water respectively, and performing water bath heating to prepare colloid containing titanium and doping element; and 2, cooling the prepared colloid to room temperature, transferring into a high-pressure-resistant container, adding a thermal decomposition type compound into the colloid, then quickly sealing the container, heating to perform reaction, preserving heat, obtaining precipitate after the reaction is finished, filtering the precipitate and washing with the de-ionized water and then drying to prepare the composite anatase type titanium dioxide visible light catalyst. The method has the advantages that: 1, the catalyst is prepared under the condition of 80-100 DEG C, and the energy consumption is favorably reduced during preparation; and 2, subsequent high-temperature treatment is not required in the method, the defect of high probability of losing the doping element through the high-temperature treatment is avoided, and the photo-catalytic performance is favorably improved.