Abstract: To ensure reliable motor running in ZJ112 cigarette maker, a motor current data acquisition system was designed by adopting current transformer, analog-digital conversion and bus communication technologies. The system was mainly composed of sensors, a signal conversion unit, a signal acquisition and data processing unit, and a host computer. The acquired current data were transmitted to the host computer through Ethernet, then transcribed into a Historian database via Intouch to monitor the current of motor and realize overload alarming. The results showed that:1) The maximum relative error between the current acquired value and actual value was 1.56%, less than allowable error range of ±2%. 2) The filter cutting motor in MAX was online monitored, the motor current gradually increased with the rise of load until overload alarming. The system is helpful to the prediction of motor's running status and the maintenance work.