In the article definition, content and sign structure of social solidarity asphilosophic-legal concept are investigated, the most important aspects of its researching aredetermined on the basis of Semiotics of Law’s and Philosophy of Law’s methodology. The articlestates that the term «solidarity» is meant a sense of mutual belonging and its practical support,bringing people together for a common purpose, support movements, organizations orindividuals on the basis of proximity or commonality of views and interests, consistencyin the statements, actions. Also, this term is used to refer to the collective responsibility reflectedin the formula «all responsible for one, and the one responsible for all».The broad understanding of the concept of solidarity (out of its individual forms and types),that provides for review of the whole of humanity as organically integrated structure, thesolidarity of economic interests, solidarity as a sociological fact and ethical principle, the categoryof «public service», the organic combination of the freedom of every individual and of solidarityin the community, in which there is no the well-being of the individual without welfare, onthe other hand — there is no full flowering of society without freedom and well-being ofthe individual, personal interpretation of solidarity, in accordance with that the basis of solidarityis that everyone needs in communication and cooperation to develop their personalities andsurvive, while each community needs the cooperation and participation of each of its membersto carry out their task are considered. Related to the political and legal solidarity signconstructions — subsidiary (as a constructive, social and legal principle) and the competition ofcreativity (that provides the dynamics of development of economic relations) are defined.The paper shows methodological meaning of Semiotics of Law for the development ofthe modern Philosophy of Law and possibilities of its use as the paradigmatic approach inthe theoretical and methodological basis of research of political and legal phenomena, inparticular, of social solidarity. It is stated that the exploration of Semiotics of Law methodologycould enrich Philosophy of Law with the new knowledge of functioning principles of differentlegal system’s elements and mutual relations between main forms of reflection of solidarity as asign construction in the political and legal reality.