Abstract: In order to detect sliver content in cut tobacco rapidly and accurately, an online detection device was developed on the basis of multistage fluidizing principle. The device is mainly composed of a fluidizing chamber, cut tobacco suction pipes, a cut tobacco collecting box and a dust collecting box. The cross-sectional area of the fluidizing chamber varies alternately between two set values along the air passage to separate slivers from cut tobacco thoroughly. The cut tobacco of a certain cigarette brand was tested in Guangzhou Cigarette Factory, the results showed that the absolute errors between the measured value and theoretical value of sliver content in cut tobacco ranged from 0.007 9% to 0.188 1%, the standard deviations ranged from 0.295 0% to 0.862 3%; both the accuracy and precision met production requirements, the preferable sampling volume was 150 g, and the preferable number of repeated tests was 30. When the sliver content in cut tobacco is higher than 3%, the increase of sliver content does not influence the absolute error, relative error and standard deviation of test results significantly. This device provides a technical support for rapidly and accurately detecting the sliver content in cut tobacco during primary processing.