This dissertation is the first systematic study of contemporary Chinese site-based art, a mode of art practice that takes place in everyday urban spaces such as city streets, construction sites, and other unconventional locations. Combining extensive archival research and artist interviews, the study concentrates on the “long 1990s,” a period I have defined to include parts of the late 1980s and early 2000s. The “long 1990s” brings into focus a set of discursive issues and a corresponding set of socio-structural conditions including rapid urbanization, increased transregional mobility, and a growing market economy—both of which motivated site-based art practice. While many scholars have examined urban art practices in China during this period, I draw specific attention to the growing importance of working “on-site” to reveal how questions around site and space became central to contemporary Chinese art practice. Site-based art practice in China had roots in the late 1980s but flourished in the 1990s as more artists began to literally take to the streets to merge their art and their own physical bodies with the everyday realities of the here and now. Although this form of art practice was in dialogue with site-based art practices in Europe and North American, I demonstrate the ways in which it was distinct, particularly in its integration of both site and time, a crucial aspect that current discourses around site-specificity overlooks. I develop the term “on-site” (xianchang), which was first used by Chinese filmmakers and artists in the mid-1990s to describe aesthetic practices that take place on-location, as a culturally specific yet expansive conceptual framework to understand site-based art practice. While recent attention to politically committed, socially engaged art has prompted aesthetic practices to be seen as either a passive reflection of socio-economic realities or a form of resistance against them, I show how working on-site allowed artists and their artworks to become active and critical participants in the social sphere without holding a predetermined social or political agenda. Considering how these art practices contributed to the expansion of physical, discursive, and social spaces, I reveal the ways in which on-site art practices articulated new forms of cultural expression in the public realm, transformed overlooked areas of the city into centers of social exchange, and linked these centers to sites abroad. Through four roughly chronological, thematic chapters that move from Chengdu and Lhasa, to Guangzhou, Beijing, Paris, and Berlin, the dissertation provides a transregional account of on-site art in China and an analytical method for examining how these practices emerged from and interacted with each local context. Through this history, I explore a set of interrelated questions: Why did artists begin working on-site during this period? How did they incorporate specific sites into the formal language of their art practice? And what were the aesthetic and socio-political stakes for doing so? By framing site-based practice as a form of space-making, I illuminate how art, urban social life, and the built environment mutually transformed one another during a period of unprecedented urban change. My research demonstrates that since the 1990s Chinese artists have expanded static notions of site to connect the spatial and temporal specificities of local sites to multiple other sites within a transregional, global context.