Sui generis autonomous law order of the European Union has separate system of legal acts to regulate relations in accordance with the statutory documents of the European integration organizations. Evolution of the EU legal instruments secures stability and effective functioning of the integration union. The EU Law sources are not composed into the constant system that can unify all sources to the comprehensive whole from the one side, and from another side can adjudicate the criteria for its separation into re independent components, unlike sources of national law. Fixing forms of the EU norms are formulated as the determinating factor of the European integration development that have own features accumulating elements of the international and national law sources. Lisbon Treaty doesn’t change the whole system of the sources, otherwise following the practice, the Reform Treaty classifies legal acts into category of legislative and nonlegislative. By the way of dissolution of legal acts in the framework of the former «second» and «third» pillars the EU obtains single structure and dissolution of its pillars structure. Article 288 TFEU contemplates that the Union shall exercise its competences by the way of adopting regulations, directives, decisions, recommendations and opinions. The tendency of systematization of acts was described as well as their role in the EU external relations.