Abstract:         In recent years, underwater image enhancement and restoration technology has become an important means to promote the development of underwater target detection, marine biological recognition, seabed surveying, and other fields, which has significant academic importance and application value. Firstly, the mechanism of underwater imaging is reviewed and analyzed, and the difficulties and challenges brought by hardware equipment, climate constraints, artificial light sources, and particle interference in current underwater imaging technology are pointed out. Secondly, the related works of underwater image enhancement and restoration technology are comprehensively introduced, and the relationship and difference between the two schemes are analyzed. Meanwhile, the current mainstream underwater image enhancement and restoration methods are classified and discussed in detail from the perspectives of technical routes, and the characteristics of different classification methods are pointed out through experiments. Thirdly, the commonly used underwater image datasets and image evaluation indicators are summarized, providing comprehensive and detailed technical guidance for current underwater image enhancement and restoration work from the perspectives of data support and quality evaluation. Finally, the feasible development directions of future underwater image enhancement and restoration technology in application scenarios, degradation methods, and evaluation indicators are predicted and analyzed, especially highlighting the enormous potential and practical value that current artificial intelligence can play in the field of underwater image enhancement and restoration.