Abstract: It was found that the performance of cylinder cut tobacco dryer become worse.The moisture content of output tobacco fluctuated beyond the tolerance of standard deviation 0.17%.By analyzing the steam and drainage pipelines in the dryer,the fault was attributed to the wear of rotary packing gland.Therefore,the internal diameter of compression nut was enlarged and a compression spring added to keep the packing always in a tightly compression state and prevent steam from leaking into cycling water pipeline.After improvement,the standard deviation of output moisture content reduced from 0.26% to 0.12%,the fluctuation of steam pressure and cycling water temperature decreased obviously,and 527 tons of steam and ￥68.5 thousand were saved per year.