This paper examines the transnational practices and identity formation of sci-tech returned overseas Chinese in Hangzhou. Based on in-depth interviews, participatory observation, and policy-text analysis, it argues that their return should not be understood as a linear process of permanent resettlement, but as an open-ended form of return. These actors use Hangzhou as a strategic node for entrepreneurship, career development, and resource conversion, while maintaining overseas legal status, global markets, family arrangements, and future mobility options. Hangzhou therefore functions as an “interface city” that connects local innovation ecosystems, policy resources, overseas networks, and transnational capital. The study further shows that their social connections are increasingly organized around projects, industries, capital, and professional qualifications rather than traditional native-place or kinship ties. Their identity as returned overseas Chinese is produced through the interaction of mobility, local embeddedness, and organizational recognition.