In recent years, the route optimization of intelligent ships has attracted increasing attention in academic and industrial circles. Aiming at the problem of intelligent ship route optimization, this paper expounds upon the characteristics of various route design methods and route optimization algorithms. Combined with the latest research results over the past five years, the development status of intelligent ship route optimization technology at home and abroad is analyzed, and route optimization design methods are summarized into three kinds, namely those based on meteorological data, fuel consumption models and route/waypoint databases, and the technical connotations and applications are analyzed. The characteristics and shortcomings of the improved isochrony method, dynamic programming method, graph search algorithm, intelligent algorithm and artificial intelligence/machine learning algorithm are analyzed in depth, and the main problems existing in the application of various algorithms to intelligent ship route optimization are summarized. Finally, the development trend of intelligent ship route optimization is briefly predicted to provide ideas for future research in this field.