Abstract: During the operation of limestone gypsum wet desulfurization system, a large number of impurities will be enriched in the absorber system during operation. The impurities mainly come from various dissolved and non dissolved substances carried by boiler flue gas, process water supplement, desulfurizer and cascade utilization of waste water. After enrichment, various impurities cannot be discharged from the absorber in time, which will cause deterioration of slurry quality, and then affect the operation of dehydration system, and even affect the pH value of the absorber Control of slurry density, desulfurization efficiency and other key indicators. This paper mainly analyzes the factors such as the difficulty of slurry dehydration in the absorption tower, the reduction of desulfurization efficiency and the difficulty in controlling various operation indicators of the absorption tower due to the deterioration of slurry quality during the operation of the wet desulfurization system in Huaneng Qinbei Power Plant, and looks for methods and means to improve and reverse the adverse operation mode according to the analyzed influencing factors, so as to finally ensure the healthy, stable and economic operation of the desulfurization system.