The invention discloses a longitudinal-torsional resonance ultrasonic vibration device, and relates to the field of ultrasonic processing and precise cutting. The problems that when an existing torsional vibration device applied to milling machining carries out torsional vibration, internal friction of a material loses most energy, and consequently, the torsional amplitude is small, and the energy utilization efficiency is low are solved. The device comprises a ladder type hollow cylinder cone composite body, a longitudinal-torsional conversion hollow cylinder, a pre-tightening bolt, the even number of piezoelectric ceramic pieces and a plurality of electrode pieces; the ladder type hollow cylinder cone composite body is mainly composed of an axial locating shaft, a cylindrical longitudinal-torsional conversion body, a conical torsional vibration amplifying body and a cylindrical longitudinal vibration amplifying body which are coaxially and sequentially arranged and are manufactured into a whole; and the ladder type hollow cone composite body, the longitudinal-torsional conversion hollow cylinder body, the even number of piezoelectric ceramic pieces and the electrode pieces are connected together through the pretightening bolt. The longitudinal-torsional resonance ultrasonic vibration device is used for ultrasonic vibration machining.