Abstract: The longitudinal-torsional ultrasonic motor is characterized by low speed, high torque. However there are still many problems to be discussed in its system model. it concerned the properties of this kind of motor. The characteristics of this kind motor are studied according to the manufactured sample from the angels of theory and experiment. On the basis all kinds of factors that influenced the mechanical characteristics are analyzed, at the same time the transfer-efficiency on the contact surface is calculated, the low-efficiency of this kind motor is explained. In addition, the wide-working-frequency-range properties of this kind motor are verified by experiments.