The invention relates to a seismic wave measuring system based on micro-structure optical fiber distributed sound wave sensing. The system comprises a narrow-line wide laser source, a coupler, an acousto-optic modulator, an erbium-doped fiber amplifier, a balanced photoelectric detector, a micro-structure sensing optical cable, and a signal control and processing module. The narrow-line-width laser generates signal light, and the signal light is injected into the micro-structure sensing optical cable through the circulator, and the optical cable is used for measuring external seismic wave signals. A reflected light signal carrying the seismic wave information and the reference light form a heterodyne signal to be sent to a balance photoelectric detector. The output electric signals are finally demodulated by the signal control and processing module, and effective measurement of seismic wave signals is achieved. The system has the advantages of being high in measurement sensitivity andhigh in spatial resolution. Compared with a traditional electrical detector, the system is simple in structure, small in size, light in weight and easy to install and is not subjected to electromagnetic interference. The system can be used in the fields of measuring seismic wave signals of underground transmission, resource detection, geological exploration and the like.