The aim of the article is to highlight the results of the analysis of existing approaches to statement and solution of problems of evaluating the economic security level of the region in the context of its territorial systems, and develop the author’s own scientific and methodical approach to evaluating the economic security level of the region’s territorial systems and modeling its threshold values on the basis of discriminant analysis and Euclidean distance. In view of the available statistical information, taking into account the results of our own previous studies of the problematic of economic security management, there calculated the integral index of economic security for territorial systems of the region, as well as the index of social tension in the territorial systems of the region, which became the basis for the development of discriminant models of determining security threshold levels. The analysis of the results obtained after using the discriminant models as well as models developed on the basis of the analysis of the weighted Euclidean distance has shown that they are comparable and complementary in their nature. In other words, the proposed methodologies can be successfully used in the practice of formulating strategies and target programs of regional development.