Late Carboniferous (Pennsylvanian) ostracods are described from East Junggar in Xinjiang Uygur Autonomous Region (referred here as Xinjiang) of northwestern China. Twenty-one species belonging to 11 genera are recognized. Among them, two are new, Acratia xinjiangensis sp. nov. and Healdianella shiqianensis sp. nov. These species can be referred to the Ostracod Assemblage-3 (OA-3) of the Shiqiantan Formation, and together with zircon U-P dating suggest a probable Moscovian-Kasimovian (middle-late Pennsylvanian) age for the unit. The OA-3 found in the lime-stones of the Shiqiantan Formation inhabited in open oceanic island arc context that is ecologic-ally equivalent to the Eifelian Mega-Assemblage, and incorporated smooth-podocopid associations. The Shiqiantan Formation OA-3 thus implies a foreshore to offshore environmental transition within a post-collision rift basin.