A distributed optical-fiber acoustic sensor is an acoustic sensor that uses the optical fiber itself as a photosensitive medium, and is based on Rayleigh backscattering in an optical fiber. The sensor is widely used in the safety monitoring of oil and gas pipelines, the classification of weak acoustic signals, defense, seismic prospecting, and other fields. In the field of seismic prospecting, distributed optical-fiber acoustic sensing (DAS) will gradually replace the use of the traditional geophone. The present paper mainly expounds the recent application of DAS, and summarizes recent research achievements of DAS in resource exploration, intrusion monitoring, pattern recognition, and other fields and various DAS system structures. It is found that the high-sensitivity and long-distance sensing capabilities of DAS play a role in the extensive monitoring applications of DAS in engineering. The future application and development of DAS technology are examined, with the hope of promoting the wider application of the DAS technology, which benefits engineering and society.