The invention discloses an axial ultrasonic transducer. The axial ultrasonic transducer comprises an adjusting screw 1, a pressurizing body 2, a sealing sliding column 3, an encapsulating oil 4, a center rod 5, an upper cover plate 6, an axial piezoelectric ceramic ring 7, an insulating sleeve 8, a copper electrode plate 9, a lower cover plate 10, a joint ring flange 11 and a vibration isolation ring 12; the pressurizing body and the joint ring flange are fixedly connected together through bolts; an inner cavity structure used for containing the encapsulating oil is formed in the pressurizingbody, and a thin-wall structure is adopted at the bottom of the inner cavity structure of the pressurizing body; the adjusting screw, the sealing sliding column, the pressurizing body and the encapsulating oil provide pre-tightening force required by the axial piezoelectric ceramic ring; the vibration isolation ring is inlaid at the upper end of the upper cover plate; the upper cover plate, the copper electrode plate, the axial piezoelectric ceramic ring and the lower cover plate are assembled together through the center rod; and the copper electrode plate is connected with an ultrasonic powersupply, and the axial ultrasonic-frequency electric energy is converted into axial supersonic-frequency mechanical energy during operation. When different copper electrode plates are connected with the ultrasonic power supply, axial ultrasonic waves with different frequency bands and different energy conversion efficiencies can be obtained.