The widespread development of gated communities has generated much concern over urban fragmentation and social segregation. The social division and segregation between residents inside and outside urban enclaves exist not only in their residential spaces, but also in their values, social relations, and daily lives. In this study, it is argued that sociospatial segregation research should pay more attention to individuals' actual usage of urban space in their daily lives. By examining the activity space of the residents from different types of neighborhoods, a spatiotemporal approach to studying sociospatial segregation in Beijing, China is described. Significant differences are found in the usage of time and space between residents inside and outside the so-called privileged enclaves. Their activity spaces are found to vary significantly in terms of extensity, intensity, and exclusivity. The study suggests that the fragmentation of urban space is the result not only of residential segregation, but also of how different social groups spend their time and use urban space.