To promote the environmental ecological control and water quality protection in the reservoir basin, this paper takes Changtan reservoir in Taizhou as the research object. Based on the driving force-pressure-state-impact-response (DPSIR) model, 17 evaluation elements and 35 evaluation indexes are selected to construct the evaluation index system of Changtan reservoir ecological safety, and the weights of each index are determined by expert scoring method and entropy method. According to the ecological safety index (ESI), the ecological safety of Changtan reservoir basin in 2016 is evaluated. The results show that the ecological safety index of Changtan Reservoir is 75.78 in 2016, which is in a relatively safe state; and the soil erosion intensity index is on the edge of "poor" state in resource constraints. Therefore, soil and water conservation management should be strengthened. The aquatic biodiversity in the reservoir is poor and the species is single, hence, the ecological conservation of the reservoir should be strengthened; the centralized treatment rate of urban domestic sewage and rural domestic sewage in the reservoir basin should be greatly improved. Meanwhile, the construction of sewage treatment facilities and pipelines should be strengthened.

Changtan Reservoir; ecological security assessment; assessment model; Ecological security index