Abstract: The defects of original electric control system and pipeline system in YG6801 cut tobacco dryer were analyzed, the system was upgraded by the application of field bus and other advanced control modes.The control of moisture content and temperature of output cut tobacco was discussed in detail, and the improvement of pipeline system was discussed also.After control system modification, the running reliability of the dryer was increased, the stability of processing parameter was ensured, and cut tobacco quality was improved obviously.