Recent intensive eco-city development in China has been accompanied by rising enthusiasm for environmental sustainability indicators. Whilst there are calls for the indicators to be standardised, and criticism of the difficulties in applying them, little effort has been made to understand their scientific rationale. This article employs a comprehensive bibliometric analysis to investigate the use of environmental indicators from the Tianjin Eco-City Key Performance Indicators by the international scientific community working on urban sustainability. The findings draw a clear picture of the place of Tianjin Eco-City’s indicators in the international scientific literature. China’s ecological problems are found to attract interest not only from domestic researchers but also researchers outside the country. The indicators are used not only for urban planning and management but also for a wide range of urban-related and non-urban-related purposes. The scientific rationale of the eleven indicators is specifically addressed, revealing a number of underlying questions about the Tianjin Eco-City indicators.