Abstract: Maritime transportation is one of the most important modes of human transportation. Maritime cybersecurity is crucial to avoid financial losses and ensure shipping safety. Due to the obvious weakness of maritime cybersecurity, maritime cyberattacks are frequent. There are a lot of research literatures about maritime cybersecurity at domestic and abroad, but most of them have not been reviewed yet. This paper systematically combs and comprehensively introduces the structure, risks and countermeasures of the maritime network. On this basis, some suggestions are put forward to deal with the maritime cyberthreat.