Based on the theory of system theory, environmental value theory and humanland relationship theory, this paper constructs the “pressurestateresponse” evaluation model of ecological security of reservoirtype tourism destination, and uses fuzzy set pair analysis to quantitatively analyze the ecological security level of Tianmu Lake in Liyang City in 2005 and 2015，and its spatial and temporal differentiation characteristics, and through information entropy to explore the key factors of ecological security changes. The results show that the ecological security status of the tourism priority development area in the downstream of Shahe Reservoir is poor, and the ecological security situation in the surrounding area of Daxi Reservoir is better. On the time scale, the ecological security level of all regions has been improved, and the ecological security level of the tourism priority development zone has a large positive fluctuation. The study shows that tourism development factors, population factors and environmental response policy factors are the key factors to determine the ecological safety of Tianmu Lake.

Key words：reservoirtype tourist destination; ecological security; spatial and temporal differentiation; influencing factors; Tianmu Lake