Abstract: Aiming at the problems of poor processing quality and high processing cost of small holes in ceramics, a rotary ultrasonic assisted grinding process for small holes in zirconia ceramics was designed.Firstly, the principle of rotary ultrasonic machining was analyzed.Then, under the condition of ultrasonic vibration, the single factor small hole grinding experiment of zirconia ceramics was carried out by using diamond tools.The morphology of the inner wall of the small hole was analyzed and the roughness was measured.Finally, the influence of spindle speed, ultrasonic power and feed speed on the surface roughness of the small hole was studied.The results show that, compared with conventional grinding methods, the surface quality and residual stress of small holes are greatly improved and that the machining accuracy is obviously improved with surface roughness decreased by 52% under the condition of 300 W rotary ultrasonic assisted machining.