The sintering semi-dry desulfurization by-product, desulfurization ash, has not been fully utilized due to its complex composition and large fluctuation of component content. A new method for preparing sulfuric acid after the newly generated sulfur-containing flue gas is introduced into the activated carbon desulfurization tower instead of part of the fusing agent is proposed, and industrial tests are carried out. The results show that during the sintering process, desulfurization ash mainly undergoes decomposition and reduction reaction, and 97% sulfur brought by desulfurization ash enters the sintering flue gas. Adding desulfurization ash has little effect on the composition, quality and yield of sinters, and the consumption of solid fuel increases slightly, but when the addition is greater than 0.15% and the utilization factor of the sinter machine drops significantly. Due to the large design surplus capacity of activated carbon desulfurization and denitrification system, the desulfurization efficiency of the system has little impact, but the residual amount of subsequent acid production system is insufficient, and when the amount of desulfurization ash added exceeds 0. 15%, the actual sulfuric acid production decreases by 25%. It is completely feasible for desulfurization ash to enter the sintering treatment, but the amount of addition should not exceed 0.15% of the raw material ratio.