Working-residential spaces segregation has become a pressing issue, exacerbated by the unequal allocation of spatial and social resources within contemporary metropolitans. However, limited research has delved into working-residential spaces segregation through the lens of urban space allocation, and few studies have investigated the interplay between policy and spatial segregation within urban expansion. To deepen our understanding of the triad relationship among government, residents, and spaces in the urbanization process, it is essential to promote the rational allocation of spatial resources, mitigate the conflict between working-residential spaces, and bolster the government's socialized governance and sustainable regulation. Therefore, this study takes Chengdu as a case to identify working-residential spaces, and categorize working-residential spaces segregation into nine types, analyzing the segregation of its spatial functions and working-residential spaces segregation. Results show that spaces segregation varies considerably between inner-outer cities, and that urban expansion of outer cities has not alleviated working-residential spaces segregation. In terms of spatial distribution, the inner cities have a large number of residential spaces, while working spaces are located in the west and south sides of the outer cities. In terms of work-residential spaces segregation, the segregation is much more severe in the outer cities than in the inner cities, especially in the government-planned high-tech zone and new districts, which show extremely severe spatial segregation. Critically, the study challenges the efficacy of constructing new districts in resolving urban segregation. It contributes valuable insights into comprehending urban spatial equity and justice through the lens of urban spaces, offering a reference point for the enhancement of urban social governance.