Abstract: In order to reveal the impacts of Spartina alterniflora invasion on macrobethos communities, during October 2004 to January 2005, we studied the distribution pattern of macrobenthos and its correlation with soil factors in Jiuduansha intertidal mudflat of the Yangtze River estuary. We selected 57 sample sites representing six habitat types, i.e., Phragmites australis, Scirpus mariqueter, S. triqueter, and Spartina alterniflora plant communities, and low tidal and high tidal mudflats. A total of 28 macrobethos species were found, consisting of Mollusca, Annelida, Crustacea, and Insect larva, with the dominant species being Stenothyra glabra, Assiminea violacea, A. latericea, Limnodriu hoffmeisteri, and Ilyrplax deschampsi. The low tidal mudflat supported more species abundance of macrobenthos, but low density, whereas the habitat of Scirpus mariqueter held the highest density. Statistical analysis demonstrated that Pielou evenness index significantly differed between bulrush areas (Scirpus mariqueter) and other habitat types. Further analysis revealed that habitat dominated by the invasive species Spartina alterniflora supported average species richness and density of macrobenthos, although some species were absent.