Abstract: In order to narrow the difference of cigarette weight between the front and rear tobacco rod passages, the secondary stem separator in ZJ116B cigarette maker was modified as following:1) Designing two independent mechanisms to control the stem separation of the front and rear passages independently. 2) Changing the straight-through separation passage into a Z-shaped one. The test results showed that:1) The average SD of individual cigarette weight from the front passage decreased from 14.40 to 13.16 mg and that from the rear passage reduced from 16.08 to 13.44 mg. 2) The difference of average SD lowered from 1.68 to 0.28 mg, and the fluctuation of individual cigarette weight reduced obviously. 3) The content of fiber in stems decreased from 18.4% to 9.0%, it meaned better stem separation and lower tobacco consumption.