In the article idea of peace, its place in the sign elements of the idea of law and the most important aspects of its researching are investigated on the basis of Semiotics of Law’s methodology. The article states that the term «peace» is meant commonly as the period between wars that have characterized diplomatic relations between groups of people, nations and states, and the corresponding state of harmony in society. Proposed and discussed a broad understanding of the concept of peace, which implies a state of social relations in which real system of institutions and mechanisms, designed to prevent the emergence of new social conflicts and effectively help to resolve existing social contradictions, is established. The contents of related legal sign structures, such as freedom, justice, common good, solidarity and order are defined. Methodological possibilities and heuristic potential of the productive use of the semiotics approach in the process of researching of the idea of law are determined.