Eco-city construction is a key node in China's urban transformation and development, and plays a driving role in China's ecological civilization and new-type urbanization development. Taking Xiamen, a typical eco-city in China, as an example, by calculating the emergy flow of the urban metabolic system of Xiamen, this study constructed an emergy index evaluation system for Xiamen from 2010 to 2017 based on the combined emergy analysis of urban metabolism, selection of emergy sustainability index, emergy index of sustainable development, emergy index of urban health, comprehensive evaluation of the ecological sustainability. Some emergy indexes were compared with Zhuhai and Shenzhen, in order to provide scientific reference for the sustainable development of eco-cities in China. The results showed that (1) the total emergy of Xiamen's metabolic system presents an upward trend from 2010 to 2017, and the total emergy of 2017 is 2.51×10²⁴ sej, which is 1.65 times of the total emergy of 2010. The emergy of money flow shows a significant increase, and the emergy of waste is gradually decreasing from 2010 to 2017. The emergy self-support ratio of metabolic system in Xiamen gradually increases from 98.30% to 99.20%, the emergy yield ratio gradually increases from 8.30% to 15.20%, and the environmental loading ratio is less than 3, which belongs to the environmental low load state. (2) The emergy sustainability index between 1-10 shows that the ecological economic system has the vitality and development potential. The emergy index of sustainable development increased from 3.67 in 2010 to 7.76 in 2017, showed that the sustainable development of Xiamen is better. The emergy index of urban health rose from 6.21 in 2010 to 25.80 in 2017, showed that Xiamen's ecological system is in a state of healthy and sustainable development. (3) The comparative analysis of the emergy index of Xiamen, Zhuhai and Shenzhen shows that Xiamen and Zhuhai are both in the stage of abundant economic vitality and great potential of ecological sustainable development,and the metabolic system of Xiamen is better than that of Zhuhai and Shenzhen in terms of sustainable development. (4) In general, under the construction of eco-city, Xiamen's urban metabolic system is in the stage of sustainable development. The construction of eco-city is conducive to the sustainable development of Xiamen's ecological economy, and this study has theoretical reference value for the construction and sustainable development of the same type of eco-city in China.