Abstract: An index system of ecological risk assessments for Guan River estuary was established based on pressure-state-response (PSR) model theory and different ecological quality factors were also taken into consideration, such as coastal economic development, regional main pollutant discharge, pollution treatment, environmental management level, environmental condition and social service function of this area. Then ecological risk assessment indexes of Guan river estuary were calculated based on the investigation and monitoring data in 2011 and 2019. The ecological risk indexes were 54.7 and 32.6 respectively, belonging to the low ecological risk level. However, the index in 2011 was close to the lower limit of medium ecological risk level. Therefore, control measures were forced to carried out under the pressure. After comprehensive pollution treatments, the ecological risk index decreased significantly in 2019, close to the very low ecological risk level. It shows that the index system of PSR model ecological risk assessment has important guiding significance for regional pollution prevention and scientific remediation.