The general purposed wideband transducers (including low frequency to high frequency) are generally used in combination with different types of transducers. A single transducer is independently designed and then combined into an array. Its size is large and itsweight is heavy, and its performance specifications are affected after installation, such as the opening angle of the transducer becomes smaller. Based on the analysis of the current research status of broadband transducer at home and abroad, combined with the requirements of small remote operated vehicle (ROV) on the board detection, this paper puts forward the specific design requirementsof the underwater acoustic transducer. The composite rod transducer and several piezoelectric ceramic rings are designed in an open and integrated way. On the basis of meeting the installation requirements of small ROV, the ultra widefrequency band coverage of 3~100 kHz for transmittingand 1~100 kHz for receiving is realized, and the opening angle is not less than 70°. The actual aviation test on the pool and the lake proves that the developed transducer is in line with the simulation design, the actual measurement results are in good agreement with relevant domestic and foreign conclusions, and have extensive engineering practical value.