Abstract: Wet flue gas desulfurization (WFGD) is the key technology for the desulfurization of flue gas in coal-fired power plants,which will produce a large amounts of desulfurization gypsum,and the preparation of green building materials,such as gypsum mortar,is an important way for their high-value utilization. However,due to water recycling in the desulfurization system and the requirement for zero discharge of desulfurization wastewater,the content of chloride ions in desulfurization gypsum is generally high,which seriously restricts the quality of gypsum mortar. Therefore,it has become a current research hotspot to control the chloride ions in desulfurized gypsum in order to suppress its adverse effects on the performance of gypsum mortar products. Firstly,the influence of chloride ions on gypsum mortar was introduced in detail,including the effects of Cl-on the hydration process of gypsum and its performance of water absorption. Then,the current control technology of chloride ions was systematically introduced,including physically adsorbing chloride ions and blocking the channels of chloride ion migration,and chemically converting to the water-insoluble chloroaluminate. In addition,the detailed preparation parameters of gypsum mortar from WFGD gypsum with high chloride ion contents were summarized. When the calcination temperature is 150-180 ℃ and the duration is 1.5-2.5 hours,the obtained gypsum has higher density and lower porosity,which can hinder the migration of chloride ions. Retarder can prolong the setting time of gypsum,but it is not conducive to the control of chloride ions migration. Waterretention agent can improve the water retention of gypsum mortar but will accelerate the migration of chloride ions. Superplasticizer can decrease the water/ash ratio,which can suppress the migration of chloride ions. Water-proofing agent can improve the pore structure of the gypsum,which inhibits the formation of calcium chloride. Finally,the developing trend of gypsum mortar preparation from WFGD gypsum with high chlorine ions was also proposed.