Abstract: Taking the chemical process of a single-tower ammonia desulfurization system as an object of study, numerical simulation was carried out to its adsorption, neutralization and oxidization process using Aspen Plus process software, so as to obtain corresponding parameters, such as the material flow and components at each nodal, chemical reaction condition, desulfurization efficiency and product quality, etc., and analyze the influence of main process parameters on the desulfurization efficiency. Results show that the desulfurization efficiency rises with reducing inlet mass concentration of SO₂ and increasing Liquid-gas ratio, which may reach 95% at an liquid-gas ratio of 7.5-10 L/m³. The efficiency increases with rising flue gas flow and liquid ammonia quantity; however, when the liquid ammonia quantity gets up to a certain value, the desulfurization efficiency starts falling instead of rising.