Abstract: Evaluating ecological security is very important to the construction of the ecological security. The technologies of remote sensing (RS), geographical information system (GIS), and analytical hierarchy process (AHP) are used to evaluate Sichuan ecological security. The appraisal index system suitable for Sichuan is created at first, which is composed of three layers such as object, rule, and index. The 14 indexes indicate respectively the status of nature, human culture, society and environmental pollution. The indexes are obtained and calculated by using RS and GIS. The weights of the indexes are determined by using AHP. The relative models are created for evaluating the ecological security. Finally, the indexes of the natural ecological environment, human culture society pressure security, environmental pollution pressure security, and regional ecological security are calculated and graded by using the relative models and GIS. It is shown that: the regional ecological security can be effectively evaluated by using RS, GIS and AHP.