The article examines the main features of Russian classical church and secular architecture in the context of pan-European development. The author highlights the relationships of iconographic sources and internal and external factors which determined the architecture of Russian classicism as a unique phenomenon in world practice and formulates the main modes of formation and evolution of the national Classicist architecture: a unique fusion of various stages, creative methods and artistic styles, emergence of unique style metastructures, electivity, and eclecticism. As the result, the author proposes a classification of planning and compositional structures. The uniqueness and variety of Russian classical architecture acquires the value of a kind of compendium of regional historical architecture.