The article states that in the national tradition of law the issue of law system is deeply connected with its structure. It emphasizes that such legal category like «legal system» refers to classical instruments of legal dogma. The authors support the idea that legal rules always form a system of law, at least some logical relationship between cohesion standards. It is argued that current legal system has a complex structure; they state it is multi-layered and polistructural. Besides, scientists define legal system design factors and analyze its main features (unity, consistency differentiation and integration, objectivity and subjectivity, stability and dynamism). Authors focus the attention of a reader on the importance of separation of public and private law, on the distinction of relationship governed by them, on the difference in identifying subjects, mutual status, legal status and analyze the composition subsystems of law specified.Writers research the history of a law division to substantive and procedural law, as well as the relationship between legal system structural elements. Furthermore, they provide the reader with a detailed description of the main elements of the legal system (legal rule, legal institute, branch and subbranch of law, subsystem).