Abstract: Under the background of ultra-low emission of sintering flue gas, in order to effectively control the generation of condensable particulate matter (CPM) and the problem of colored plume, this paper aimed at the ultra-low emission typical process of "semi-dry method (dry method) desulfurization + medium-low temperature SCR denitrification" of sintering flue gas, and designed the simulation condensation experiment device by referring to the principle of dilution indirect method. The interaction and mechanism of condensation of NH₃, HCl, SO₃ and H₂O in sintering flue gas were investigated based on the thermodynamic and kinetic simulation results of atmospheric aerosol. The experimental results show that the existence of escaping NH₃ will cause the nucleation rate of SO₃ to increase significantly. Form sulfate aerosols with low deliquation point and easy agglomeration, so that the average condensation ratio of SO₃ increases to 84%. HCl exists mainly in the form of ion in sulfate aerosol, with an average condensation ratio up to 80%. HCl and SO₃ promote the condensation of NH₃, and the order of effect is: HCl + SO₃ > SO₃ > HCl. The average condensation ratio of NH₃ can be increased from 27% to 78%, and the change of initial NH₃ concentration has the greatest impact on the total condensation of CPM. The results can provide useful reference for effective control of condensable particles in sintering flue gas.