A new feeding mode for a simulated moving bed (SMB) is proposed. The outlet stream from zone II is collected at regular intervals. The concentration of the solution is increased by dissolving raw materials and then fed to zone III as the feed stream during the next collection interval. In this feeding mode, the concentration of the stream fed to zone III is identical to that of original feed, while in a conventional SMB, the feed is diluted by mixing with the outlet stream of zone II before feeding to zone III. The new feeding mode increases the inlet concentration of zone III. A modeling investigation shows that higher inlet concentration of zone III increases the height of concentration band in SMB, improving the separation performance significantly. In comparison with the traditonal feeding mode, the new feeding mode increases the productivity by 23.52% and decreases the solvent consumption by 22.56%, so as to increase the raffinate and extract concentrations by 53.17% and 20.38%, respectively. The collection interval for the outlet stream from zone II has no effect on the separation performance after reaching the steady state, so that the collection interval can be increased to make the operation more convenient.