The study on mechanical characteristics of rotary ultrasonic motors is incomplete in reflecting the operation characteristics of rotary ultrasonic motors. To apply the motor in servo system, it is necessary to carry out further research on its operation characteristics. A test system for measuring operation characteristics is built, with the ultrasonic motor of TRUM-60 type produced by Jiangsu Fengke Ultrasonic Motors Technology Co. Ltd as the test specimen. Because the output frequency and output voltage are regulated independently in the system, mechanical characteristics and regulation characteristics of the ultrasonic motor can be measured. Test results show that both characteristics are uniform functions, which can satisfy the requirements of the servo motor′s operation characteristics. The rotary ultrasonic motor can thus be used as a servo motor.