Abstract: Ecological security assessment is a new research field of sustainable development,and the basis of ecological security warning system construction and environment management.This paper introduced the concepts of ecological security assessment,including ecosystem health assessment,ecological risk assessment,ecosystem service assessment and ecological carrying capacity,summarized the current assessment indicator systems,and analyzed the evaluation methods,which include mathematical model method,ecological model method,landscape ecological method,and digital terrain model method.Problems in practice were put forward,and hot topics in future were mentioned,e.g.,transition from static assessment to dynamic prediction and warning,combination of the assessment with modern science and technology,and with basic theories.

Key words: Soil particle fraction, Organic carbon, Total nitrogen, Distribution