Abstract: An open-hole broadband transducer using multi-mode coupling is proposed.A rectangular through hole is opened at a certain distance from the front cover of the traditional longitudinal vibration transducer to excite the vibration mode that is coupled to the longitudinal vibration and is beneficial to broaden the frequency band.state.The factors that affect the working bandwidth of this kind of transducer include the length and width of the through hole and the distance between the front end of the hole and the end surface of the front cover.The finite element method is used for structural optimization design and vibration radiation characteristics analysis to obtain the best opening size.The transducer prototype was made.The test results show that the transducer has three main operating modes within 12-32 kHz,and the latter two modes contribute to the widening of the operating bandwidth.The test results show that the-3 dB bandwidth of the same size longitudinal vibration transducer without a hole is only 3 kHz,and the corresponding maximum transmitting voltage response is 148 dB,while the holed transducer has a bandwidth of 10.5 kHz and a maximum transmitting voltage response value of 141 dB.It obviously expands the bandwidth.The theoretical calculations and experimental results are in good agreement.In addition,the holed transducer proposed in this work maintains the evenness of the face of the front head,and compared with the same size longitudinal vibration transducer,its front face will also have a larger amplitude,which can be effectively applied in civil fields such as ultrasonic cleaning.