According to test results and almost one year's application experiences of desulfurization additives in limestone-gypsum wet flue gas desulphurization system for a 600 MW thermal power generation unit,the effect of desulfurization additives on safe economic operation of desulfurization system and the attentions in the application process are analyzed in this paper.Results show that desulfurization additives can improve the efficiency of sulfur removal,reduce the operational cost,expand the scope of using fuel and enhance the flexibility of operation.Moreover,the effective concentration of the desulfurization additives and the quality of limestone should be guaranteed when the desulfurization additives are used.