Abstract: When creating a color bank,those foreign matters whose color is relatively close to tobacco leaf are apt to be recognized as acceptable tobacco by the color bank of a tobacco sorter,which results in a lower rejecting rate of foreign matter.Foreign matters of larger area or volume are hard to be rejected because of air velocity or other factors.Therefore,a color bank filtering method was proposed to reject the foreign matters whose color is close to tobacco leaf,and a specially designed alarm device would be triggered when larger foreign matter was detected,then they were manually rejected.The experiment results showed that the reliability of the system was improved and the rejecting rate of foreign matter increased from 90% to 97%.