Abstract: A wetland ecosystem health evaluation index system is established by taking into integrated consideration of the standards for ecosystem health and the ecological characteristics of estuarine wetlands, and using the PSR (pressure-state-response) model as reference and from the aspects of pressure, environmental status and biological response. And besides, the catastrophic p rogression method was used to analyze and assess the health status of the Liaohe estuarine wetland ecosystem in 1996 and 2000. Results show that the healthiness of the ecosystem was 0.979 1 in 1996 and 0.961 8 in 2000, which suggests that the ecosystem declined in health condition, from heath to sub-heath as a result of inadequate of water resources and increasing petroleum pollution. It is, therefore, essential to intensify management of oil exp loitation,rationalize distribution and use of water resources and ensure water supp ly to the wetland ecosystem so as to p romote ecosystem health of the Liaohe estuarine wetland.

Key words: Liaohe estuarine wetland, ecosystem, health assessment, catastrophe theory, the PSR model