We live in a world full of political, economic or social borders, and our lives are always constructed and changed by borders, while the political dimension of border is well documented, other dimensions, such as the social dimension, cultural dimension, and interaction within bordered area, are not. Through field investigations and in-depth interviews, this paper discusses the formation and development of Chung Ying Street border area between Shenzhen and Hong Kong, a border area with a history of more than a century, currently located between two systems (socialism and capitalism) in one country. Chung Ying Street was the result of the Britain's lease on the New Territories in the late 19th century. Since the reform and opening-up policy, Chung Ying Street has witnessed great changes in its function, role, status and socioeconomic structure. Most notably, the boosting economy and tourism have greatly influenced the mundane practices and life space of border inhabitants. This paper explores how the border affects the spatial construction of the study area, and how border inhabitants adapt to and utilize the border through mundane practices. By examining the dynamic interactions between border inhabitants and border in different stages and bottom-up rebordering by residents, this paper finds that: First, under borders impact on Chung Ying Street, the spatial formation can be demonstrated as a spatial construction process, since both sides are managing the border, and residents from both sides are adjusting to negotiating with and even actively utilizing the border. In this process, border governors, inhabitants, tourists, parallel traders and other forces are constantly interacting with each other, reflected by different stages of development in Chung Ying Street area. Secondly, border inhabitants' transition from passive adaptation to active utilization of the border effect, indicates the fundamental principles of survival strategies and life space in their mundane practices. Based on the empirical study, this paper concludes that: (1) The construction process among the border, border inhabitants and border spaces might have gone through several cycling phases, during which the three actors are constantly interacting with each other in different ways; (2) Through routine practices, the border has been "instrumentalized" as a crucial survival-strategic means by border inhabitants in the context of "one country, two systems". In summary, to investigate the meaning of borders and the process of life space formation in a border area through "bottom-up" lens from the inhabitants' perspective, this research not only extends research viewpoints and enriches empirical cases, but also provides a better understanding of the formations and developments of border space. Practically, this research lays a sound foundation for further political implications concerning border governance in China.