In recent years, Polycentric urban areas have become widespread as a spatial reality, analytical framework, and normative approach. While most researchers are focused on the structure of these regions and the assumptions such as economic competitiveness, territorial cohesion, and environmental sustainability; understanding the potential of planning in such areas is yet limited because planning in Polycentric urban systems is relatively in a new scale which is based on new strategic goals. This paper studied the problem from the planning perspective and focused first on the role and necessity of the regional approach in developing Polycentric urban areas. Then, by accepting this essential, a framework waspresented to apply a regional approach in these areas, i.e., the central Mazandaran urban complex, emphasizing the three dimensions of spatial-functional integration,institutional capacity, and culture-identity as a planning prerequisite. The results revealed despite the potential of complementary relations and everyday culture in this region, the immaturity of public organizations and institutions, and the lack of legal boundaries for the urban complex, the urban complex of central Mazandaran is a product of competition between cities rather than being the result of cooperative relations.