Base on the heterodyne laser Doppler theory, a heterodyne laser Doppler vibrometer(LDV) with fiber structure was designed and implemented . The sensitivity and communication rate of the system, and the influence from water surface wave were tested in anechoic tank. The experimental results show the smallest detectable sound press of 105.6 dB/μPa. On hydrostatic water surface, the acousto-optic communication rate reaches 5 kbit/s without error; some signal is Dropped on hydrodynamic water surface, but using the spread-spectrum modulation, the acousto-optic communication rate reaches 30 bit/s without error.