Abstract: A research on semi-dry FGD technology using CFD-DEM method is conducted to study the motion of wet particles and their performance on SO2 remove. The liquid bridge force model proposed by Mikami (1998) et al. is introduced to estimate the interactionamong wet particles. The reaction rate of desulfurization is calculated depended on the two-film theory. The profiles of particle volume fractions, velocities and the main forces on particles are obtained. Simulation results indicate that liquid bridge force facilitates the formation of particle aggregation. Meanwhile, the distributions of particles are more inhomogeneous, which result in a decrease on SO2 removal efficiency. Furthermore, the effect of humidity on the desulfurization is also investigated by adjusting the parameter of dimensionless liquid bridge volume. As the humidity increases, the agglomerate grows and the SO2 removal efficiency increases first and gradually decreases. Simulation results of SO2 removal efficiency are in a good agreement with the experimental data from Kunio Kato (1999) et al.