Abstract: Traditional fieldbus has the disadvantage of frequent network failures because of its poor reliability and resistance to disturbance, difficulty in installation and liable to have loose contact.The control system in 12000 kg/h threshing and redrying line of Guizhou Bijie Shuntai Tobacco Limited Corporation adopted Rockwell redundant ControlNet industrial fieldbus, distributed I/O, and industrial Ethernet technologies.The configuration, design of software and hardware, and main functions of field operating station were analyzed.The practical running of the tobacco threshing and redrying line proves that the control system is stable and reliable, its looped industrial Ethernet and redundant ControlNet filedbus are helpful in improving real-time control and reliability, and the system is ease of integration, extension and maintenance.