Rotary ultrasonic machining has been widely used in processing all kinds of hard and brittle materials. It is a new type of composite processing method and has advantages of good surface quality, high machining precision, little tool wear. The design of the mechatronics system for rotary ultrasonic machining was focused on. With ACR9000 controller as the core and Cyclone as the drives, the control circuit was designed and installed. By adjusting PID parameters, the machine was running smoothly and the movement precision inspecting for each axis was done. At present, the mechatronics system with 4 DOF is accomplished and four axis linkage is realized. It lays foundation for ultrasonic experiment at later stage.