Abstract:Ultrasonic vibration cutting is more and more widely used in machining hard materials,but its application in boring is scarce.The performance of vibration system affects the quality of ultrasonic machining directly.Experimental results show that the singledimensional vibration can’〖KG-*2〗t meet the progressive requirements of machining.A kind of longitudinaltorsional horn for ultrasonic vibration boring was designed.The principle of modal transformation was stated, the structure calculation and motion analysis were made.The mode analysis,transient dynamic analysis and harmonic response analysis were carried out by means of finite element analysis software ANSYS.It provides theoretical basis for the structure design and performance optimization of ultrasonic vibration system,which is used for compound ultrasonic vibration boring.