Abstract: Eco-city construction is an urgent priority to coordinate urbanization and ecological development, and thus becomes the frontier and focus of sustainable development research. At least 220 Chinese cities, townships, states and regions have been certified as eco-city until 2016. This task simultaneously received praise and criticism from international academia. Therefore, in order to find the right path for China’s eco-city development, it’s necessary to analyze the latest eco-city research progress and development trends, clarify research themes, and explore construction directions. In this regard, this paper uses bibliometric method and knowledge graph visualization technology to analyze the features of eco-city publications from 2009 to 2018. The amount of publications, the authors and their affiliations, the journals as well as the citation index are investigated. The cooperation networks between various universities and research institutes are also explored. Then, the research themes in different periods are revealed. It was found that the amount of eco-city publications between 2009 and 2018 was 3983, showing a rapid growth trend. China’s influence in the field of eco-city research is prominent, but the average number of citations needs to be improved. Countries with higher urbanization have cooperated closely in the field of eco-city research. Universities and research institutes are the main body of eco-city research. Although they have initially formed a cooperative network, the degree of contact and cooperation is still low. The keywords with high frequency of eco-city research are urbanization, urban ecology, ecosystem services and sustainability, etc., which have a high degree of centrality. Facing the opportunities provided by new technologies, eco-city research should promote multidisciplinary integration, in-depth study of the nonlinear and complex characteristics of urban composite ecosystems. In the face of global climate and environmental changes, eco-city research should also focus on coupling mechanism for some key natural elements such as food-energy-water nexus, and some key subsystems such as socio-ecosystem.