Abstract: Recent years have witnessed the rise of platforms such as Facebook and Google. Gigantic in scope and becoming omnipresent, these platforms are acquiring qualities of infrastructure, which is large-scale connected systems that support people’s activities invisibly. Recent scholarship has identified WeChat, the most popular mobile social platform in China, as infrastructure. WeChat follows a platform logic to expand, and by conforming to the Chinese government’s techno-nationalist focus, it has gradually become an infrastructure in China. We contribute to the understanding of platform infrastructuralization by taking WeChat as a case, highlighting the user’s role in this process. We find user contributes to WeChat’s infrastructuralization through a three-level interaction process: to practice, to appropriate, and to create. By calling out the user’s role in platform infra-structuralization, we discuss how the CHI community can contribute to a better understanding of this phenomenon.