Longitudinal torsional ultrasonic vibration-assisted milling （LTUVAM） is an auxiliary milling technology that applies high-frequency micro amplitude vibration in the axial and torsional directions of the tool. It has many advantages，such as reducing cutting force and cutting heat， improving the surface quality of the workpiece， increasing residual compressive stress on the surface，and reducing tool wear. This paper presents a systematic review on the milling of difficult to machine materials. In terms of equipment manufacturing，the structural design method and working principle of longitudinal torsional ultrasonic vibration system were described；In terms of process development，the cutting performance of various materials was analyzed from the cutting edge motion track and the cutting characteristics of LTUVAM. The advantages and applications of LTUVAM are summarized. Finally，this paper provides an outlook on the future development trends of LTUVAM.