Abstract: To reduce labor intensity and avoid tobacco jam,tobacco flow interruption and frequent start/stop operation in manual operation of the discharge from the silo type tobacco feeder,an automatic discharge speed adjusting system was designed with industrial Ethernet and distributed programmable control technology. The system was mainly composed of a programmable logic controller, frequency converters, motors and photoelectric switches. By monitoring the status of photoelectric switches installed on the high,middle and low levels of metering tube,the running frequencies of bottom belt and elevating belt were adjusted. The results showed that the automatic system reduced manual adjusting from 26 to 3 times/batch,tobacco jam,tobacco flow interruption and start/stop of equipment decreased from 3.4 to 0.2,from 2 to 0.2,and from 182 to 36 times/batch,respectively. It ensured the consistent tobacco flow supplying to the downstream equipment.