Abstract: A co-vibrating three-dimensional optical fiber vector hydrophone (OFVH) based on the optical fiber accelerometer with integrated structural design is proposed. Utilizing the integrated structural design and its working principle of mass-spring system, the optical fiber accelerometer with integrated structural design is developed. On this basis, a three-dimensional OFVH is designed and fabricated using the push-pull configuration and six optical fiber accelerometers. The OFVH is measured using standing wave tube comparison method and differential delay heterodyne demodulation technique, the results show that the OFVH has a relatively flat frequency response of acceleration phase-shifted sensitivity in the frequency range of 20–500 Hz. For the X channel, the average sensitivity is about 34.7 dB (re. 1 rad/(m·s⁻²)), close to the sound particle vibration theoretical calculation result (36.5 dB) and the finite element simulation result (35.5 dB).