Urban green space (UGS) plays an essential role in sustainable urban development and is closely related to public health and human well-being. The inequity of UGS violates environmental justice and threatens the life quality of residents. Although previous studies have examined UGS distribution and the disparity between social groups, they seldom consider the spatial heterogeneity of the UGS inequity for the vulnerable. To find out which vulnerable groups are suffering the insufficiency of UGS resources and to identify the specific spaces with severe UGS inequity in the context of high-density cities, this study employed a geographically weighted regression (GWR) approach to investigate the spatial relationship between UGS availability and neighborhood vulnerable socio-economic variables in Guangzhou, China. Results showed that the older adults, less-educated population, immigrants, and households with a living area below 50m2 in more than half of the neighborhoods in Guangzhou were suffering UGS inequity. These neighborhoods were detected spatially and had different spatial agglomeration characteristics. Based on this, the UGS inequity level of each neighborhood was comprehensively evaluated so that we can identify the spaces facing serious UGS inequity issues that should be paid attention to in future UGS system planning and policymaking. •GWR was employed to investigate the spatial heterogeneity of UGS inequity.•Some vulnerable groups, especially the immigrants, are not exposed to green space equitably.•Neighborhoods suffering UGS inequity were detected spatially.•Specific areas facing serious UGS inequity issues should be the priority in future planning.