In order to solve the disposal problem of coke oven desulfurization ash and semi-dry desulfurization ash in large iron and steel enterprises, the two are blended as desulfurizers to replace part of the limestone in the "limestone-gypsum" wet desulfurization process, and the physical and chemical properties of desulfurization ash are analyzed by particle size detection and SEM, XRF, XRD, TG-DTG and other characterization methods, and the effects of gas temperature, inlet SO₂ concentration, gas flow, liquid-gas ratio and slurry pH value on desulfurization efficiency under different desulfurization ash blending ratios are tested in order to explore the optimal blending ratio of desulfurization ash under the optimal quality of desulfurization gypsum. The results show that the particle size distribution of coke oven desulfurization ash is uniform, the pore structure is loose, and the main components of sodium carbonate alum, Na₂SO₄ and Na₂CO₃, both play a promoting role in wet desulfurization. The blending of the two desulfurization ashes can improve the uniformity and fluidity of the desulfurization slurry, and solve the problem of low desulfurization efficiency of semi-dry desulfurization ash directly used in wet desulfurization. In addition, the desulfurization efficiency decreases with the increase of gas temperature, inlet SO₂ concentration and gas flow, and increases with the increase of liquid-gas ratio and pH value. Blending an appropriate proportion of coke oven desulfurization ash can improve the desulfurization performance, especially at low temperature, high SO₂ concentration and fast gas velocity. In general, when the blending ratio of desulfurization ash in coke oven is 5%, the desulfurization effect of the desulfurizer and the quality of the gypsum produced are the best, and the average desulfurization efficiency can reach more than 96%, and the quality of desulfurization gypsum can still meet the national third-level gypsum standard and the national soil pollution risk control standard.