Abstract: Research literature on ship energy efficiency in 1990~2021 is searched in Databases CNKI and WOS (Web of Science). Based on the processing result of software CiteSpace, the Knowledge Graph in Ship Energy Efficiency is constructed in terms of number of papers, author, organization and keyword. The trend of ship energy efficiency and topics of general interest in the field are analyzed, mainly from the angle of ship technology, operation and policy. The research shows that the number of papers in the field has increased tremendously since 2018. The clustering on keywords indicates that most Chinese papers concern EEDI, ship energy systems and CO₂ emission. As for English papers, the most interested topics are ship energy system, CO₂ emission and waste energy recovery. Further analysis, dividing the energy efficiency into energy efficiency technology and operational energy efficiency, indicates that the technologies connected with alternative energy sources are widely discussed because of the introduction of EEDI; waste energy recovery technology attracted wide attention, but only a short period; and the researches about EEOI and SEEMP focused on speed optimization and energy management strategy.