In the process of ultrasonic vibration cutting (UVC), the resonant frequency of mechanical syntonic system varies in a wide range because of system's heating up and variable loads. If the ultrasonic power doesn't work at the resonant frequency of mechanical syntonic system, UVC is not able to go along continuously and stably. In order to solve the problem, the composition of an UVC system is introduced simply. Then, the electrical characteristics of ultrasonic magnetostrictive transducer are analysed. Finally, a method, with which to adjust the working frequency of the ultrasonic power in accordance with the phase-shift-frequency curve of ultrasonic magnetostrictive transducer, is presented. Experimental results indicate that this method can make UVC system work continuously and stably at situations of variable cutting conditions.