A rate model, which considers axial dispersion, external mass transfer, intraparticle diffusion and nonlinear isotherms, and ports periodic switching is adopted to simulate the simulated moving bed (SMB) process. The effects of flow rate in Sections 2 and 3 and switching time on the operating performance parameters: purity, recovery, productivity and desorbent consumption are studied. A simulation approach is applied to simulate the operation and performance of the SMIB. The model predicts the performance of the transient and cyclic steady state behavior to a reasonably good extent, and provides guidance operation condition of the SMB process.