A new dynamic model is developed for analyzing the dynamic process of piezoelectric stepmotors. In this model the voltage applied to the piezoelectric stepmotor is equivalent to the force acting on the end of the piezoelectric stepmotor. The model is simple and convenient for applications. As an example, a model of analyzing the rotatable sample stage is presented. The theoretical results are in good agreement with the experimental results. The structural damping of the piezoelectric material is also discussed.