Abstract: Safe, intelligent, and efficient navigation have been pursuing by various fields of the shipping industry.The 12th International Conference on Marine Navigation and Safety of Sea Transportation (TansNav 2017) manages to promote the developments of ship navigation safety, intelligence, and energy efficiency optimization.Keynote speeches and technical papers are statistically categorized and analyzed from the perspective of ship navigation optimization, the hot topics including ship collision avoidance, ship domain, human reliability, intelligent ship, and energy efficiency optimization are summarized, and their applications in the field of ship navigation optimization are introduced.The challenges of ship navigation optimization in terms of navigation safety, intelligence, and energy efficiency optimization are illustrated.Finally, the main trends of future ship navigation optimization are given, including the design of safety management and decision-making system, development of navigation brain system, studies on intelligent energy efficiency management and fleet energy efficiency optimization based on big data, etc.