Ecological security is as important as national security, economic security, and financial security, and it has become the main constraint of future socio-economic security. The security of the forest, as the main part of a terrestrial ecosystem, has a significant influence on ecological balance and determines the sustainability of the social economy of humans and the availability of future resources. Based on the interaction between the forest ecosystem and human society, this paper evaluated the security of the forest ecosystem from two perspectives:the condition of forest ecology (Ecological Condition Index, ECI) and pressure from human activities (Ecological Pressure Index, EPI). We used a forest ecological security state-pressure model, and employed the forest ecological security index (ESI) methodology, to verify ESI theory from fifteen experimental unit countries in five provinces.. The annual forest ecological security index (1999-2003) was evaluated and applied to relevant studies, such as the evaluation of the Country Forest Ecological Security Index, and the comparative analysis of temporal and spatial patterns.