Abstract: Resonant frequency shift of ultrasonic transducers is common phenomena in the application of high power piezoelectric ultrasonic transducers, which results in poor power conversion and poor amplitude. In this paper , based on magnetostrictive material Tb-Dy-Fe (TDF) and piezoelectric ceramics Pb(Zr,Ti)O3（PZT）layer composite vibrator , magnetically tuned mechanical resonances were achieved with effect of magnetostrictive material and magnetoelectric coupling product effect. The interaction between an external magnetic ?eld and the polarization of piezoelectric materials is one way to achieve such a magnetodielectric effect (ME). It was found that the resonant frequency of piezoelectric composite vibrator significant shift with increasing dc magnetic field , which resonance frequency offset were about 15kHz when the magnetic field intensity was 400mT . Both in magnetoelectric coupling theory and experiment result, the frequency shift with dc magnetic field have the same behavior. Besides, the relationship between the volume fraction of magnetostrictive material and resonant frequency shift were also presented. Experimental and theoretical analysis showed that such magnetically tuned variation in resonant frequency originates from the magnetic field-induced change of the compliances of the magnetostrictive phase of the composite. The results show that the resonance frequency offset increase gradually with the increase of magnetostrictive phase volume fraction. Because of large frequency shift and high sensitivity, the present magnetically tuned resonant frequency can be widely used in magnetic sensors, ultrasonic transducers. As we have used only dc magnetic ?eld that tuned electromechanical resonances, theadjustment manner can simplify application in ultrasonic transducers.