Abstract: Based on the enlargement of fine particles by heterogeneous condensation, removal of particles from LIFAC (Limestone Injection into the Furnace and Activation of Calcium) desulfurization system was investigated experimentally. Supersaturation required for fine particles growth was achieved by adding adequate steam to the wet flue gas at the inlet of condensation chamber. The enlarged dusty droplets were removed by a high efficiency demister. The particle number concentration, size distribution, temperature and humidity were measured in real time by ELPI (Electrical Low Pressure Impactor) and Vaisala humidity transmitter, respectively. The influences of activation water addition amount, steam addition amount, particle number concentration and demister on the removal of fine particles were investigated. The results indicate that supersaturation improve at first and then drop with the increase of steam addition amount. The removal efficiency of fine particles can be effectively improved by heterogeneous condensation. The removal efficiency rises with the increase of supersaturation, decrease of particle number concentration and the enhancement of performance of the demister.