Abstract: In order to avoid the rough cut edge of tobacco rod caused by the interference between rotary ledger and Hooke cutter, the cutoff process of tobacco rod in ZJ119 filter cigarette maker was analyzed. The equivalent kinematic model for tobacco rod cutting unit was established via studying the interference mechanism between ledger and cutting blade. Three ledger settings were investigated, and corresponding minimum clearances, under which the interference was preventable, were calculated by numerical analysis combining with Adams simulation. The results showed that: 1) In the cutoff process of tobacco rod, the interference was mainly caused by the displacement difference between the blade and the ledger in the axial direction of tobacco rod at the points of cutting in and cutting out. 2) The minimum clearances for one-side, both-side, and front- and rear-row clearance settings were 0.63, 0.69 and 0.51 mm respectively. This method provides a support for improving the cut edge appearance of tobacco rod.