Abstract: As a fundamental project of building of a modernized country, the construction of physical borders involves the establishment and management of border markers and other functional infrastructure, which are profoundly influenced by prevailing border concepts. This paper seeks to demonstrate the interactive logic between ideas concerning border and building of physical border by reviewing the historical evolution in this respect through three historical periods, i.e. the elastic boundary view under the early-Qing tianxia (all the world under heaven) ideology around the second half of the 17th century, the territorial allocation-focused border perspective from the late Qing Dynasty (1644-1911) to the Republican era (1912-1949), and the multifunctional border concept adopted after the founding of the People's Republic in 1949. Corresponding to these conceptual shifts, China's physical border construction practices have undergone significant transformations. Influenced by the tianxia worldview, the pre-Qing dynasties largely neglected physical border delineation and made errors such as the separation of demarcation and border marking, unilateral border marking, voluntary territorial concessions, erroneous border markings and ambiguous border records, leaving vulnerabilities later exploited by imperialist powers to encroach upon Chinese territory. During the semi-colonial period since 1840, constrained by foreign powers, China lacked the capacity for “proactive construction” and “effective maintenance” of its physical borders, resulting in haphazard demarcation efforts, weak border control, and simplistic border infrastructure development. Only after 1949 when the People's Republic gained full sovereignty did the State begin conducting meticulous boundary surveys, constructing multifunctional border facilities and implementing robust border governance. The study demonstrates that the shift from “flexible and ambiguous” territorial concepts to “sovereign and rigid” ones serves as the core ideological driving force behind the transformation of physical border construction from reactive adaptation to proactive construction.

Key words: modern state, physical border, border concept, border construction