Abstract: The bandwidth of a transducer is increased by doubly exciting with a matching layer.The vibrating modes of the transducer with doubly exciting plus a matching layer in air are analyzed by using finite element method(FEM),and variations of modes with its geometry size and the matching layer material in water are studied.A new triple resonant broadband transducer is designed and made to attain an increase of almost one octave bandwidth and the fluctuation within bandwidth is relatively flat in con-trast with only doubly exciting or only a single matching layer.The bandwidth of the transducer is 15 kHz～42.5 kHz and the TVR fluctuation within bandwidth is ±3 dB.