After the founding of the People’s Republic of China, the cross-border cities in its minority area, especially the Tumen River area, has been confronted with two main issues: “stability” and “security.” However, the long borderline not only plays a role of “blocking” but also “connecting.” This article aims to understand the multifunctional aspects of borderlands by introducing various theories of border region studies. It analyzes the opportunities and challenges and that the administration of the border is facing, such as mutual cooperation, transnational migrations, social disintegration, self-identification, etc. Taking San Diego-Tijuana as an example, these cross-border cities should not be considered as politically or socially sensitive zones but instead bridges that promotes the development and the communication of communities on both sides of the border, drawing on the advantages and avoiding the disadvantages.