The invention relates to the ozone low-temperature catalytic oxidation technology, and provides a method for producing sulfuric acid by catalytic oxidation of sulfur dioxide in flue gas via ozone coupling with manganese dioxide/aluminum oxide. The method includes cooling the flue gas passing through a selective catalytic reduction (SCR) reactor, injecting ozone, introducing the flue gas into a reaction tower with a desulfurizer, and performing oxidizing reaction to oxidize sulfur dioxide into sulfur trioxide, allowing the sulfur trioxide to enter into an absorption tower with the flue gas, and spray-washing the sulfur trioxide by 98.3% concentrated sulfuric acid to obtain the sulfuric acid product. The method of the invention performs catalytic oxidation of sulfur dioxide by using ozone coupling with manganese dioxide/aluminum oxide desulfurizers to produce sulfuric acid. The method of the invention has renovating significance in view of existing SCR coupling wet desulphurization devices; existing desulfurization towers can be transformed and integrated with the method, so as to achieve high-efficiency desulfurization denitration and effective sulfur resource recovery, save investment cost, and gain second income. The method of the invention can further treat organic matter and carbon monoxide while desulfurization.