Abstract: To better master the technology of filter rod cutoff system incorporating with rotary ledgers, the filter rod cutoff system in the DF10 twin-track filter rod maker was analyzed. The working principle of the cutoff system was studied using the velocity analysis and the trajectory equation to develop mathematical models of the cutoff system. The mathematical models were calculated by Visual Studio software with the C++ programming language and the mathematical models was fitted with Matlab software. Creo software was used to simulate the relevant working status and validate the mathematical models. The results showed that: 1) The inclination angle of the knife carrier was determined by the length of the filter rod, the cutoff diameter of the knife, and the positions of the front and rear tracks. 2) The rotational radius of the ledgers was determined by the length of the filter rod, the number of ledgers, and the positions of the front and rear tracks. 3) The rule of self-rotation of the cutoff knife was determined by the inclination angle of knife carrier and the cutting point of cutoff knife. 4) The slope of the filter rod end was determined by the inclination angle of knife carrier, the positions of the front and rear tracks, the length and diameter of the filter rod, and the shape of the knife edge. The results calculated by the developed mathematical models were compared with the corresponding values provided by GD Corporation and the values measured by a 3D model in the corresponding working status; it was found that the deviations were neglectable. The developed mathematical models provide theoretical guidance for upgrading and modifying cutoff systems in filter rod makers.