Urban morphological characters have implications for town-plan regionalization but have received little attention. This paper systematically reviewed urban form aspects, built form and morphological characters. The review highlighted built form is a reference aspect that coordinates other aspects of urban form and contains hierarchical plan-element complexes. Such complex relationship within the built form is vital to give urban form its morphological characters. Since urban morphological characters regionalize town plans, this role merits more study to establish relationships among morphological characters, town-plan regions, and sustainable development. There is also a shift to study town-plan regionalization in support of urban landscape management.