This paper reports a novel all polarization-maintaining optical fiber vector hydrophone.The all polarization-maintaining optical fiber interferometer structure can prevent signal fading due to random changes in the polarization state of the guided beams.The signal fading caused by random phase-shift in the interferometer is eliminated by the phase generated carrier(PGC) technology.The sensor is all-optical,which is convenient to be applied for long distance detection and transmission.The sensitivity and frequeny band of the sensor are enhanced by optimizing the structure.The acceleration sensitivity reaches 33 dB and the fluctuation is less than 1 dB in frequency band of 20-2 000 Hz.The phase sensitivity is-155 dB at 1 000 Hz.The optical vector hydrophone has an excellent directivity.The maximum asymmetric index is less than 0.4 dB and the directivity index is greater than 45 dB.