Rapid urbanisation leads to increasing conflict in the human-environment relationship. The health of urban ecosystems is deteriorating and this will directly harmcommunity health and wellbeing. This paper used Kunming, the capital city of Yunnan Province, China as a case study. A health assessment model for the urban ecosystem of Kunming was built using 25 indicators reflecting five measures: driving force, pressure, state, impact and response. We calculated the indicator values in 2006, 2011 and 2016 with remote sensing and statistical data. We used the entire-array-polygon method to draw polygon graphs and calculate the overall indicator values of the three periods, based on the standardised values of all indicators. All the indicator values were below 0.25, showing that the urban ecosystem was assessed as unhealthy. On the basis of the past health assessment model, we applied a grey system forecasting method to predict the future health of the urban ecosystem. If the current trends continued, the urban ecosystem would remain in an unhealthy state for 5–10 years. Strong measures should be implemented to improve the overall health of the urban ecosystem. This paper serves as an early warning of the health state of the urban ecosystem in Kunming.