Since the promulgation of "Water Pollution Control Action Plan " in China, zero liquid discharge of desulfurization wastewater has become a new trend of power plant water pollution control. Aiming at the application of desulfurization wastewater evaporation technology using high-temperature flue gas, simulation and experimental research on quantifying and predicting gas-solid partitioning of chlorine ion under different operation conditions are carried out in this paper. The gas-liquid equilibrium theory is applied to the complex mixed salt system; based on state equation, the semi-empirical model of gas-solid phase partitioning coefficient of chlorine ion is calculated, with high degree of fitting range from 180 to 380°C. The essential effects of pH, Cl- concentration, and total dissolved solids (TDS) on the gas-solid phase partitioning coefficient of chlorine ion are investigated. The study provides key data for the application of evaporation technology using high-temperature flue gas, obtaining the quantification and prediction of chlorine ion volatilization during desulfurization wastewater evaporation.