The invention discloses a method for preparing precipitated barium sulfate by utilizing titanium white waste acid, belonging to the technical field of comprehensive utilization of titanium white wasteacid and preparation of barium sulfate. The method comprises the following steps of adding ammonium hydroxide to neutralize with titanium white waste acid firstly, then generating ammonium sulfate, and controlling a systemic pH to separate out photodegredation sediment; then adding the ammonium hydroxide continuously, and controlling the pH to separate out ferrous hydroxide sediment; then addinghydrogen peroxide in proportion, oxidating residual Fe2<+> into Fe3<+>, and adjusting the pH to separate out ferric hydroxide sediment; condensing an ammonium sulfate solution, then replacing a mirabilite solution in a traditional precipitated barium sulfate production process, enabling the ammonium sulfate solution to generate replacement reaction with a barium sulfide solution, and washing, drying and smashing to prepare a precipitated barium sulfate product. According to the method, after neutralizing the titanium white waste acid with the ammonium hydroxide and performing purification andimpurity removal, a traditional sodium sulfate solution is replaced for producing the precipitated barium sulfate, meanwhile, recycled photodegredation sediment can be further used for titanium dioxide production, not only are resources saved, but also waste can be recycled, and the waste acid treatment costs of titanium dioxide plants and environment protection pressure are reduced.