The flue gas after wet desulfurization carries a lot of water content and energy, so it is an effective method to improve the thermal efficiency of the boiler by recovering the water and waste heat through spray condensation.The numerical model of spray condensation is established, and its rationality is validated with exptl. verification.The effects of structural parameters such as spray layer spacing, spray angle, the relative position of spray layer, nozzle d., condensing tower height, and operating parameters such as droplet diameter, liquid-gas ratio, spray water temperature, spray speed, flue gas velocity, and flue gas temperature on outlet flue gas temperature were studied.The results show that droplet diameter, liquid-gas ratio, spray water temperature, spray speed, and nozzle d. have a great influence on flue gas temperature reductionThe optimal design parameter is determined with the droplet diameter less than 210 μm, the liquid-gas ratio greater than 3 L/Nm3, and the nozzle d. of 19 nozzles/m2.