SO2 in flue gas needs to be eliminated to alleviate air pollution.As the quality of coal decreases and environmental standard requirements become more stringent,the highefficiency desulfurization of flue gas faces more and more challenges.As an economical and environmentally friendly solution,the effect of calcium formate as an additive on desulfurization efficiency in the wet flue gas desulfurization (WFGD) process was studied for the first time.Improvement of the desulfurization efficiency was achieved with limited change in pH after calcium formate was added into the reactor,and it was found to work better than other additives tested.The positive effects were further verified in a power plant,which showed that adding calcium formate could promote the dissolution of calcium carbonate,accelerate the growth of gypsum crystals and improve the efficiency of desulfurization.Thus,calcium formate was proved to be an effective additive and can potentially be used to reduce the amount of limestone slurry required,as well as the energy consumption and operating costs in industrial desulfurization.