In order to master the relationship between flexible hinge,screw rail and clamping force mechanism,a screw-type piezoelectric displacement actuator based on the inertia stick-slip principle was fabricated.The flexure hinges and clamping mechanism were designed and analyzed by finite-element analysis simulation.Applying a unidirectional sawtooth signal to the actuator,its displacement output velocity keeps stable when the frequency is below 500 Hz.The forward and backward velocities increase almost linearly with the increase of frequency and voltage.The forward and backward velocities are 11.51 μm/s and 7.98 μm/s,respectively,and the average step lengths are 23 nm and 16 nm,respectively,as the driving voltage is 48 V and the frequency is 500 Hz.The relative errors of forward and backward velocities are 12.85% and 4.21% respectively in large-stroke repeated motion,showing good displacement stability.