Oyster reefs, as one of the typical coastal zone ecosystems, hold significant ecological service values such as water purification, reduction of coastal erosion, maintenance of biodiversity, carbon sequestration. However, there is still a lack of systematic investigation into the ecological status and geographic distribution of natural oyster reefs in China. Correspondingly, scientific research in this area remains relatively limited. A systematic investigation and monitoring analysis of the distribution of the Spartina alterniflora-oyster symbiotic community and the characteristics of the supporting macrobenthic community in the intertidal zone of the western coast of Bohai Bay were conducted in June 2022, April 2023, and June 2023. COI fragment detection indicated that the reef-building species in the intertidal oyster reef was the Crassostrea gigas. According to investigations, the total area of oyster reefs in this region was approximately 19.71hm². The oyster density and recruitment showed a significant increasing trend along the land-sea gradient, with higher densities and more abundant recruitment on the seaward side. The individual shell height of oysters(≥ 20mm)ranged from 20.00 to 113.00mm, with both adult oysters and juveniles distributed within this range. There was a total of 53 species of macrobenthos belonging to 7 phyla collected in this study, including 25 species of mollusks, 16 species of annelids, 8 species of arthropods, and 1 species each of echinoderms, nematodes, brachiopods, and cnidarians. Based on NMDS and ANOSIM analysis, significant spatial differences were found in the composition of macrobenthic communities between the oyster reef distribution area and adjacent areas with only Spartina alterniflora distribution or mudflats (P < 0.05). Within the oyster reef distribution area, a total of 34 species belonging to 6 phyla of macrobenthic animals were identified, including mollusks (19 species), arthropods (5 species), annelids (7 species), brachiopods (1 species), nematodes (1 species), and cnidarians (1 species). Among these, mollusks consistently dominated the community, with slightly lower proportions of arthropods and annelid compared to the other two areas. Unique phyla present in the oyster reef area included brachiopods and nematodes. The survey results demonstrated that oyster reefs supported a greater number of species and higher levels of biomass. Furthermore, the Shannon-Wiener diversity index and Margalef richness index of macrobenthic communities within oyster reefs were also higher. Our study indicated that the emergence of newly formed oyster reef communities on the western coast of Bohai Bay has altered the composition structure of macrobenthic communities, thereby enhancing the biodiversity levels of the intertidal habitat.