Abstract: Rotary spray drying method is an important technology to achieve zero discharge of desulfurization wastewater. PDA was used to test and analyze the particle size distribution of the desulfurization wastewater from the rotary atomizer outlet, and the atomization law of the desulfurization wastewater under different operating parameters was obtained.Desulfurization wastewater was spray-dried and evaporated using a coal-fired experimental platform, and the morphology of the evaporated product was analyzed.The results show that the rotary atomizer has good speed and flow adaptability, and the atomized droplet size is mainly concentrated below 30μm.A small amount of large particle size droplets will be produced during the atomization of high-salt wastewater, but has no significant effect on the evaporation process. Good drying efficiency can be achieved when the flow ratio of hot flue gas to wastewater is in the range of 1.0～1.3*10~4 m~3/t.