The acoustic doppler current profiler (ADCP) is widely used in oceanography. It is the most important velocity measurement equipment currently. The key component of ADCP is the piezoelectric transducer, which is used to transmit and receive acoustic signals. Combined with the development of ADCP, this paper reviews the research progress of the piezoelectric transducers and arrays for ADCP, and the calibration methods of piezoelectric transducers and ADCP are briefly summarized.