Abstract: An annular ultrasonic motor driven by circle side was designed and fabricated. The mechanism that traveling wave revolves the motor rotor is expounded. According to finite element calculation and analysis, the vibration shape and the displacement contour of bending modes of the motor stator is presented. And on the basis of these calculation results, the relationship between electrode arrangement of PZT and bending mode excitation of the stator is analyzed. Results show that piezoelectric ceramic pieces used can rotate the motor with multi-frequency. The multi-frequency driven experiments of the motor have been completed. The experimental results verify the correctness of the analysis. Therefore, based on the idea presented in this paper, the problems for ultrasonic motors of other structure with multi-frequency driving can be studied.