Abstract: In order to effectively narrow quality fluctuation in filter rod making, the effects of tow opening ratio and pressure on threaded rolls and stabilizer rolls, and air jet pressure on the stability of pressure drop and hardness of filter rod were studied on KDF-2 filter maker by using three acetate tow items, 2.4Y/34000, 3.0Y/35000 and 3.3Y/37000. The results indicated that: 1) for the same tow item, the speed ratio between rolls, the pressure on threaded rolls and stabilizer rolls, and air jet pressure were the key factors influencing tow opening and filter rod forming; 2) the favorable speed ratio between rolls might be somewhat different for different tow items, the pressure drop and hardness of filter rod were the stablest when the speed ratio between rolls was controlled in the range of 1.20-1.25, 1.40-1.45 and 1.50-1.55 for the tow items of 2.4Y/34000, 3.0Y/35000 and 3.3Y/37000, respectively; 3) within the test limits, it was preferable to keep the pressure on threaded rolls and stabilizer rolls in the range of 0.18-0.20MPa and 0.08-0.10MPa, respectively; 4) to ensure the quality stability of filter rod, air jet pressure should be kept as low as possible in case that the process was not negatively affected, normally, it was not recommended to exceed 0.08MPa.