Abstract: The tobacco cutter's knives needed to be advanced to compensate for the wear while machine running. The existing wear compensation unit uses mechanical or pneumatic-mechanical driving device.A piezoelectric microdisplacement unit was developed by means of the inverse piezoelectric effect of piezoelectric ceramics, its linearity, stability, zero-resetting ability and value of delay were satisfactory both in static and dynamic states, and could be used in the knife wear compensation unit in tobacco cutter.