Abstract: In order to effectively improve the quality of combined filter rod, promote machine efficiency, and reduce waste rods, a regression model between the nozzle diameter and width of hot melt adhesive line was established via experiment, and the maximum value of nozzle diameter was solved based on technical requirements; further, the optimal diameter of the nozzle was determined by a bi-objective programming model.The appearance quality and related physical indexes of combined filter rod were validated after optimization, the results showed that:1) With the increase of nozzle diameter, machine efficiency increased first and then decreased, while the rate of waste rod was on the contrary.2)The optimal nozzle diameter was 1.5 mm, when the width of adhesive line reached 1.95 mm.3)The rate of combined filter rod with appearance defects reduced by 36%, the roundness and hardness of filter rod significantly promoted, the machine efficiency raised by 1.8 percentage points, and the rate of waste rod decreased by 49.62%.