The twophases vibrations of the stator of travelingwave type ultrasonic motor were simplified into a system of two degrees of freedom,and a dynamic equation was established sequently based on the mode assumption.The expressions for the transfer function and admittance were deduced based on the equivalent circuit, and as a result the parameters were decided through FEM calculation and experimental measurement. Based on this, a simulating model was set up for the dynamic model.The results showed that the method can be used for the parametric design and performance prediction for the stator of ultrasonic motor.