Abstract: There was heavy dust buildup in the chamber of cutting drum in SQ35 tobacco cutter, because of it's unsatisfactory dustproof system and the pressure difference between inside and outside of the drum.The problem was solved effectively by boosting the pressure in the dustproof system (including analysis of system structure, design of air circuit and improvement of outer seal), the driving device was running in relatively clean circumstances, which resulted in longer equipment life and better cut tobacco quality.