Abstract: In this paper, the physicochemical characteristic of white mud and the characteristics of white mud slurry were systematically investigated, and the influence of factors such as slurry concentration and pH on the desulfurization performance was studied. An engineering application study was carried out on a supercritical boiler unit with 2×350 MW power generation at Guodian Zhaoqing Thermal Power Co., Ltd.. The performance of white mud desulfurization and traditional limestone-gypsum desulfurization and the characteristics of gypsum by-products were comparatively studied. The results showed that the influence of white mud slurry concentration and pH on the removal of SO₂ was significant. When the slurry concentration was lower than 12.5% (5% and 8%), the desulfurization efficiency gradually decreased when the pH value decreases from 10.0 to 6.0. The influence of pH value on desulfurization efficiency was basically negligible when the slurry concentration was 12.5%. In a three-layer slurry spray packing tower, the liquid-gas ratio was 8 L/m³, and the air velocity of the empty tower is 0.4 m/s. The highest desulfurization efficiency was above 96.7%. By using the single-tower double-cycle process, the results for the engineering application of white mud desulphurization in a 350 MW coal-fired power plant showed that the effect of white mud desulfurization was better than that of the limestone-gypsum method within the operating load range of 240-249 MW under SO₂ flue gas concentration of 1948-1999 mg/m³. The desulfurization efficiency of white mud was 99.25%-99.49%, which is slightly higher than that of the limestone-gypsum method with the value of 99.18%-99.20%. When the white mud was used as the desulfurizer, the lowest SO₂ concentration at the flue gas outlet was only 10 mg/m³, meeting the requirements of the ultra-low emission standard for SO₂ control. Compared with gypsum by-products produced by the limestone-gypsum method, the white mud desulfurization gypsum by-products were essentially similar in the aspects of acid insolubility, moisture content, and other indicators and appearance; these were in accord with the requirements for building material products; and satisfied the requirements of by-product resources.