Abstract: In order to reduce flying generation in filter rod making,optimize filter rod making process and improve filter rod quality,the flying generated from tows of different moisture contents were determined under different ambient relative humidities.The air pressure of air spreaders and pressures of threaded rolls in ZL26A filter rod maker were studied with an orthogonal method,and the variation of flying amount produced at different opening ratios was analyzed.The results showed that:1) flying amount significantly reduced when two moisture content and ambient relative humidity ranged from 5% to 7.6% and 50% to 70%,respectively;2) the pressure of threaded roll affected flying amount significantly,flying amount would be effectively reduced when the pressure of two stabilizer rolls,delivery rolls and threaded rolls was 0.08,0.2 and 0.18 MPa,respectively,and opening ratio in the range of 1.41 to 1.42;3) the air pressure of air spreaders was not the main factor affecting flying amount.