Abstract: Based on the analysis of the vibration characteristics of each radiation surface of a ternary dense array of bender transducer, a method of adjusting the driving phases of radiation surfaces is proposed to increase the bandwidth of the dense array. The analysis points out that by adjusting the phase of the driving voltage of the functional material, the vibration displacement amplitudes in the outer normal direction of each radiation surface of the array increase at the second and the third order resonances, by adjusting the vibration phase difference between the radiation surfaces, the peaks corresponding to the second and the third order resonances in the transmitting voltage response (TVR) curve increase, and the fluctuation between the first three peaks in the TVR curve decrease, thereby the available operation bandwidth can be broadened. Experimental results show that the driving phase adjustment method can achieve the low frequency broadband emission effect of the dense array.