Abstract: Numerical simulation of gas-solid flow in the fluidized bed with inner partition plates had been carried out based on EMMS model coupling with two-fluid model in order to investigatethe gas-solid velocity distribution and solid particles volume fraction distribution,as well as the effect of the size of solid particles on the solid particles volume fraction distribution. The result shows the back-mixing of solid particles in the fluidized bed,and presence of the inner partition plates enhances the back-mixing of solid particles. Higher local solid particles volume fractionindicates the agglomeration of the solid particle. Heterogeneous distribution of solid particles exists in the fluidized bed,the solid particles volume fraction distribution along height direction shows“S”shape profile. With the decrease of solid particle size,the amount of solid particles being brought into the zone within 0.1 m to 0.4 m increases. The simulation result could provide theoretical guidance for understanding the gas and sold flow of magnetic roasting in fluidized bed with Inner Partition Plates.