This article contributes, in the form of theoretical discussion, to the review of relevant methods for determination of city's spatial structure through the retrospective of continuity/discontinuity of understanding their spatial structure from the school of classical sociology to the sustainable development paradigm. Particularly, authors underline significance and analyze main theories and their models (social-ecology, economics, system science and geography) in the researching of spatial structure of the cities. They conclude that urban settlements spatial structure is resultant of complex dynamically-developing processes between settlements networks and systems on the one, and also between their internal components, on the other side. In their essence, cities are not statistical category, but complex and dynamical system whose structure reflects the relations between economic, social and cultural organization of life, adapted to the geographic environment.