Exploring the relationship between ecosystem health and urbanization is the foundation for solving the ecological and environmental problems of urban ecosystems and has both theoretical and practical significance. This paper investigates the relationship between ecosystem health and urbanization in 260 Chinese cities in the years 2000, 2005 and 2010. For each city, four aspects of ecosystem health are evaluated and three types of urbanization are measured. The paper uses piecewise linear regression to explore the spatiotemporal dynamics of the relationship between urbanization and ecosystem health at both national and regional levels. Finally, the threshold levels of urbanization that cause changes in ecosystem health responses were estimated. The results show significant negative correlations between different dimensions of urbanization and ecosystem health at the national level, with spatial urbanization having a greater effect than economic and population urbanization. The results also reveal regional and temporal differences in the correlations at both national and regional levels, along with threshold levels for the effects of urbanization. This paper aims to explore the dynamic impacts of different urbanization characteristics and stages on ecosystem health, and help in reconciling the contradictions between economy, population, land expansion, and ecosystem health in different urbanization stages by identifying the thresholds of change trends.