Abstract: According to the requirements of energy saving and emission reduction policy for the 12^th Five-Year period, the bypass damper for the wet FGD system of a 600-MW unit in one power plant was plugged on May 17, 2012. Based on the comparison between the technical characteristics before and after plugging, the adverse effects of eliminating the bypass on the secure operation of the unit and the desulfurization equipment are presented. To improve the reliability of the desulfurization system, the desulfurization equipment is incorporated into the main equipment management with a series of measures adopted, such as installing a flue gas emergency spraying system, adding water pipelines to the mist eliminator, building a pipeline for slurry supply, splitting the power bus for large devices, adjusting logical protection and using additives for stable desulfurization efficiency. Since then, the desulfurization equipment runs stably, and no main equipment shutdown has ever happened due to breakdown of the desulphurization facilities.