In a spray column scrubber，the removal of fine particles by wet flue gas desulfurization（WFGD）system was investigated experimentally for the typical WFGD process，such as limestone-gypsum double-alkali and ammonia-based process.The number concentration and size distribution，morphologies，elemental and phase composition of fine particles before and after desulfurization were measured by using an electrical low pressure impactor（ELPI），field emission scanning electron microscope/energy dispersive X-ray spectrometry（FESEM-EDS）and X-ray diffraction（XRD），respectively.The influences of SO2 absorbent and liquid-gas ratio on fine particles removal by the WFGD system were also investigated.Moreover，an experiment was carried out on the removal of fine particles with high efficiency by heterogeneous condensation of water vapor.The results showed that the removal effect of fine particles by the WFGD system was related to the SO2 absorbent employed.When using CaCO3 and NH3·H2O to remove SO2 from flue gas，the fine particles removal efficiencies were lower than those for Na2CO3 and water，and the morphology and elemental composition of fine particles were changed.This effect could be attributed to the formation of aerosol particles in the limestone and ammonia-based FGD processes.The effect of liquid-to-gas ratio seemed to be relatively weak except for NH3·H2O as absorbent. The performance of removal of fine particles by the WFGD system could be significantly improved by means of steam addition both in the gas inlet and above the scrubbing solutions inlet of the scrubber，in which the removal efficiency increased with increasing amount of added steam.