Abstract: Taking the desulfurization spray gun of the alkali recovery boiler as the object,the effects of atomization particle size,injection speed and atomization angle on the desulfurization effect are studied by numerical simulation. The results show that the initial diameter of the atomized droplets has a influence on the complete evaporation time and water vapor distribution. The complete evaporation time of 400 μm droplet is 3. 96 times of that of 100 μm droplet. The effects of spray speed and atomization angle on the complete evaporation time and water vapor distribution are different,but they are far smaller than the effects of atomization particle size.