Underwater target recognition is a core technology of underwater unmanned detection，which has important applications in military and civil areas. According to the current research progress of underwater target recognition，the principles and methods of underwater target recognition based on sonar images have been comprehensively reviewed in this paper，which has positive significance for summarizing the research status， discovering the existing problems and exploring the potential research directions. Aiming at the problems of underwater target recognition based on sonar image，the main development in image denoising，image segmentation and underwater target recognition have been discussed，and the latest technology development status quo of sonar image target recognition based on deep learning has been expounded. Through the discussion and analysis of the underwater target processing process，the key scientific problems and possible solutions in the underwater target recognition algorithm that need to be resolved immediately based on sonar images are pointed out，and the future development direction of this field is further prospected.