The invention discloses a giant magnetostictive longitudinal-torsional coupled vibration ultrasonic transducer which comprises a transducer main body, a coil support and a shell, wherein the shell comprises a top plate, a base plate as well as a plurality of giant magnetostictive bar installation pipes, a plurality of giant magnetostictive bars, a first magnetic conduction sheet, a second magnetic conduction sheet, an upper cover plate, a lower cover plate, a fastening element, a magnetic element and a coil; the plurality of giant magnetostictive bar installation pipes are arranged between the top plate and the base plate; the plurality of giant magnetostictive bars are respectively installed in the giant magnetostictive bar installation pipes; the coil is reeled on the coil support; the coil and the fastening element are coaxial; and an ultrasonic frequency alternating current is introduced into the coil so as to generate an alternating magnetic field to drive the giant magnetostictive bars to generate longitudinal-torsional coupled vibration. According to the giant magnetostictive longitudinal-torsional coupled vibration ultrasonic transducer provided by the embodiment of the invention, parts are reduced; and the structure of the transducer is simplified, so that the structure of the transducer is compact, and the ultrasonic energy can be transmitted efficiently.