Abstract:The piezoelectric actuator has the advantages of fast respons,lower power and large output force,but it is difficulty to control the precise microdisplacement of the piezoelectric actuator for its hysteresis characteristics , the piezoelectric actuator must be modeled for the hysteresis characteristics to achieve the desired dynamic and static characteristics of control. The hysteresis characteristics of the piezoelectric actuator was tested, the characteristic curve was drawn based on the test, the characteristic curve equation was obtained by polynomial fitting way to satisfy a given accuracy,the model was completed. The experimental results were compared with the model output under the same input condition, the result shows that the static model error of the piezoelectric actuator is about 1%, which proves the effectiveness of the method.