A spouted bed of binary particle mixture was applied to a low temperature desulfurization process in order to develop a new type of semidry flue gas desulfurization (FGD) technology. We investigated the effects of operating parameters, such as type of SO2 sorbent, diameter of SO2 sorbent particles, apparent residence time of gas in the bed, approach to saturation temperature and Ca/S molar ratio, on SO2 removal in a bench-scale powder-particle spouted bed. We also investigated the utilization rate of SO2 sorbent and ways to enhance the efficiency of SO2 removal and SO2 sorbent utilization. The experimental results showed that SO2 removal is significantly affected by the approach to saturation temperature and Ca/S molar ratio, and that a high SO2 removal efficiency and effective sorbent utilization can be obtained under appropriate operating conditions. Thus, this new simple process of flue gas desulfurization is highly efficient and has little impact on the environment.