Abstract: Due to the high salinity and complex components, the treatment of the flue gas desulfurization wastewater is always a challenge to meet the "zero discharge" standard. Based on the mathematical model and Fluent simulation, the evaporation process of the flue gas desulfurization wastewater with droplet diameters at 50 μm and 60 μm are studied. The two sizes of wastewater droplets are vaporized in 0.78 s and 0.85 s at 130 ℃, and the compressed air consumptions are 60 m³/min and 26 m³/min, respectively. Moreover, the characteristics of the flue flow field in a 660 MW unit are also considered in the optimization of the wastewater evaporation system design. The operation data of the wastewater evaporation system are collected and analyzed for the further system optimization. Experimental results show that the evaporation of the desulfurization wastewater in the flue does not affect the flue gas desulfurization system and the electrostatic precipitator, and the variation of the fly ash is still within the resource utilization limit.