Abstract: To reduce the differences between filter rods' draw resistances caused by the changes of the remaining height of the tow bale in use, strap indentation on the tow and bonded filaments, a tow stabilizer installed at the upstream end of the primary opener was designed. The device consists of an electric control system, an elevator and a tow feeding mechanism. High-precision tension sensors in the tow feeding mechanism monitor tow tension real-timely, and then the electronic control system automatically adjusts the tow supply to ensure constant tow tension. The device was tested on a ZL29 filter rod maker making filter rods for demi-slim cigarettes. The test results showed that the designed device decreased the tow tension from 0.599 N to 0.236 N, showing a reduction of 61%, and the standard deviation dropped from 0.150 N to 0.018 N, showing a decrease of 88%. Additionally, the manual intervention in the speed ratio of the feeding roller pairs to that of the main driver decreased by about 70%. The draw resistance stability of filter rods was improved. This device provides technical support for the promotion of the automation and filter rod qualified rate of filter rod maker.