Abstract: Combined flue gas desulfurization of pyrolusite and rhodochrosite and an industrial experiment study on the preparation of battery-grade manganese sulfate were performed in a thermal power plant in Guizhou. The results show that the high-efficiency desulfurization of SO₂ can be achieved by using the pyrolusite to redox desulfurization, adjusting the pH value of pulp by rhodochrosite, and the two-stage desulfurized, and the SO₂ absorption rate can reach over 99%. The process can not only realize comprehensive utilization of lean manganese ore resources but also make the wasted SO₂ flue gas into treasure. The manganese sulfate as a desulfurization product can meet the requirements of battery-grade manganese sulfate after deep purification. Industrial test further revises and standardizes the operation rules for this process, which provides a solid foundation for industrial design and production.