The article refers to the issues of decorative elements in architecture. The aim of the paper was to reveal the interaction peculiarities of the constructive and artistic solutions of the formation of the portals of the Armenian churches of 4th-7th centuries. The analysis of the process of formation allowed for carrying out the typological classification of the portals from the point of view of the transformation and development of the lintel construction. The classification showed that the portal created as a decoration of the entrance, as a result of the evolution of compositional-structural components was transformed into a unified constructive-artistic element, which has become the main type used in the later periods of the Armenian medieval architecture. The revealed features of the interaction of decorative and structural elements can be useful in the field of heritage studies and in the development of further works on the formation of decorative elements.