As an important part of the marine ecosystem, the oceanic waters have unique biodiversity and rich fishery resources. Therefore, efficient and accurate detection of the oceanic fish diversity is an important prerequisite for the utilization and management of fishery resources. However, traditional capture-based survey methods have certain limitations. eDNA technology can be used as an important supplement to traditional survey methods due to its characteristics and advantages such as wider application scenarios, more prominent cost effectiveness, higher detection sensitivity, finer species resolution, and lower taxonomic order bias. It has a broad application prospect in the far-reaching oceanic fish diversity monitoring and fishery resource survey. This paper summarizes the current status of eDNA in the study of fish diversity and its application advantages and challenges in the study of oceanic marine fish diversity. Meanwhile, combined with the environmental characteristics of oceanic waters, we further discuss the application potential of eDNA in the study of fish diversity in the oceanic waters and possible challenges.The relevant content can provide a systematic scientific reference for further research in the future.