In this paper，a novel traveling wave linear ultrasonic motor is proposed， which uses the combination of two in-plane bending modes with same natural frequencies to form a traveling wave propagating in the circumferential direction， thereby driving the mover to move. A dynamic model considering the three-dimensional contact between the stator and the slider is established based on the finite element method. Through the model， the contact force transmission process between the stator and the slider， the driving mechanism of the motor， the elliptical motion trajectory of the driving foot at the steady state and the output performance of the motor under different input parameters are analyzed. Finally， the experiment of principle prototype is carried out. Research results show that the mechanical output performance of the motor is good， and the finite element model is reasonable. It can not only predict the performance of the motor， but also provide corresponding theoretical guidance for the optimization of the motor.