Abstract: A two-dimensional vector hydrophone is developed utilizing the PMNT relaxor ferroelectric single crystal, which is composed of a dual-axis piezoelectric composite flexural beam accelerometer and PZT-5 piezoelectric ceramic rings. Based on the principle of elastic mechanics and underwater particle velocity measurement, the receiving voltage sensitivity of the flexural beam vector hydrophone is derived. The influence of stress distribution in the flexural beam on the performance of hydrophone is analyzed, and the match between PMNT single crystal cells and the structure of flexural beam is studied. The tested results indicate that the PMNT hydrophone presents an 11 dB increase in sensitivity and a 3 dB decrease in self-noise than the PZT-5 one.