Abstract With the vigorous development of underwater acoustic technology in China, underwater acoustic transducers are constantly moving towards broadband, low-frequency, and high-power directions. How to obtain piezoelectric transducers with lower frequencies is still a research direction that scholars from various countries are striving to study. This article mainly studies and manufactures a 20 kHz single-beam piezoelectric transducer, using the classic Tonpilz transducer structure. Firstly, the Tonpilz transducer is theoretically analyzed using the classical equivalent circuit method. Secondly, the transducer is analyzed using ANSYS finite element analysis software to study the influence of piezoelectric ceramics on the frequency of the transducer, and the size of the piezoelectric ceramics is optimized to determine the size of the piezoelectric ceramic structure of the transducer. The working frequency of the transducer was calculated using software, and it was determined that the working frequency was approximately 20 kHz.