With human activities have brought tremendous pressure on the ecological environment, gradually frequent and serious disasters have become enormous threats to ecological security really or potentially. Ecological security state assessment based on Pressure-State-Response (P-S-R) mechanism in view of certain factors has become a research emphasis in this field at present, and its result reflects whole regional security condition. However, people usually pay attention not only to certain factors but also to hidden factors, not only to security state but also to security trend. In addition, ecological security is dynamic, and its evolving process, trend and risk are more important. Furthermore, Ecological security is regional and it should to be analyzed under local conditions. This paper integrated the theories of Geography and Safety Science to investigate the mechanism and methodology of regional ecological security assessment in a perspective on disaster. ①A regional ecological security state-danger integrated evaluation index system was established according to the interrelation and interplay of each part of the assessment object. This eco-security evaluation index system reflected not only security state but also potential danger; it also reflected the influences of subsystems in ecosystem, security consciousness, efficiency of response ability and measurement of behavior object. The content included multi-hierarchy state index system of P-S-R, multidimensional and multi-hierarchy potential danger index system which were established on the basis of five spheres (atmosphere, hydrosphere, geosphere, biosphere, human activity sphere). Assessment indexes were fitted for spatial evaluation based on GIS considering adequate time and spatial differences of influence factors. ② State-danger coupling index evaluation method was proposed by multi-objective decision-making rule. State index evaluation was calculated by fuzzy membership degree, and potential danger index evaluation is calculated by accident analyzing Graham method. Weights of indexes were decided by fuzzy-entropy method. Coupling indexes not only revealed eco-security state under the influence of potential danger factors, but also directed probable diversified warnings in the process of ecological security evolving. ③ A method of interactive data assignment between administration cell and gird cell was established in view of spatial variability of different security influence factors and data source types. Whole regional security was concerned, and regional security difference and reciprocity of different security attributing units were also concerned in the eco-security research. GIS technology was introduced to compute grid and vector data which are original data types of eco-security assessment model. The values of different spatial layers of arithmetic expression were assigned by Mapbasic and were realized by MapInfo and Vertical Mapper 26. ④ The assessment process was verified and evaluated spatially and visually by a case study in the reaches of Liaohe River watershed by using GIS. Eco-security state-danger integrated assessment index grid database of 2.5 km in Liaohe River watershed was established based on MapInfo. Eco-security spatial difference was evaluated quantificationally based on GIS grid technology. The results were in accord with field survey, so this method was verified that it was accurate on the whole. This work could provide decision-making support for regional ecological development strategies and plan and lay a foundation for constructing the eco-security early warning system.