Abstract: With the help of the big data analysis method and the operation experience of the wet desulfurization process, the key parameters such as the quality of the desulfurization slurry, the blockage probability of the spray layer, the leakage probability of the spray layer, and the gypsum supersaturation of the desulfurization slurry that cannot be monitored and evaluated in real time during the desulfurization operation were quantified, and specific qualitative evaluation rules were provided to better judge and guide the safe operation of the wet desulfurization. The constructed index was applied to a 1 000MW unit in North China. When there are operational operations that affect the quality of desulfurization slurry, such as replacing limestone or replacing desulfurization slurry, the developed desulfurization slurry quality index calculation value could quantitatively reflect the changes in desulfurization slurry quality; The probability of clogging and leakage of the spray layer were consistent with the operation status of the spray layer during maintenance; The gypsum supersaturation value of the desulfurization slurry of the unit was maintained at about 1.10 for a long time, and there was no scaling risk, which was consistent with the fact that there was no obvious scale on the filter screen surface and inner wall surface of the desulfurization tower during maintenance.