Through analyzing material removal mechanism of rotary ultrasonic machining, a model of machining efficiency is established and the processing parameters in the model are discussed in this article. By comparing four different materials inclding PZT piezoelectric ceramics, organic glass, glass steel and red cooper on single ultrasonic and rotary ultrasonic machining testing, the machining stabilization and efficiency of rotary ultrasonic are studied.The tests prove that rotation can significantly improve ultrasonic machining efficiency and keep the original precision.