Quantitative and qualitative sampling of zoobenthos was carried out in October 2004 and October 2009 to assess the ecological influence of a reclamation project on the macrobenthos of an East Nanhui tidal flat.The surveys were conducted each year in four sections: S1—S2 and S3—S4 were inside and outside the dyke,respectively,in 2004,while T1-T3 and T4 were inside and outside the dyke,respectively,in 2009.In total,32 species were found across all areas in 2004,Twenty of these species occurred inside the dyke and 21 species occurred outside the dyke.Twenty-six species were found in 2009 whit nine species inside the dyke and 19 species outside the dyke.On both sampling occasions,most of the macrobenthos were euryhaline species and the rest were freshwater species.From 2004 to 2009 species abundance of Crustacea,Mollusca and Polychaeta exhibited a clear decline inside the dyke,while aquatic insect abundance increased to there species inside the dyke.Outside the dyke,Crustacea and Polychaeta decreased between 2004 and 2009 but Mollusca increased by five species.In 2004,there ere eight dominant species inside the dyke,namely: Corophium sinensis,Uca arcuata,Sesarma dehaani,Ilyoplax deschampsi,Assiminea latercea,Cerithidea sinensis,Capitella capitata and Rhуacodrilus sinicus.Four species were dominant outside the dyke: Corophium sinensis,Ilyoplax deschampsi,Momoculodes limnophilus and Bullacta exarata.Corophium sinensis and Ilyoplax deschampsi were common dominant species.In 2009,Chironomid larvae were the dominant species inside the dyke and Assiminea latercea,Elachisina sp.,Glauconome chinensis and Heteromastus filiformis were the four dominant species outside the dyke.The average abundances and biomass values for macrobenthos were 44.15 ind/m2 and 38.80 g/m2 in 2004 and 86.76 ind/m2 and 1.97 g/m2 in 2009.Macrozoobenthos biomass decreased significantly between 2004 and 2009,although abundance did not decline.Data were analyzed using SPSS,one-way ANOVA,hierarchical cluster analysis and non-metric multidimensional scaling(MDS).The results of cluster analyses and MDS indicated that the eight sections were divided into four groups with different macrobenthic communities: the first group included four sections,S1-S4 from 2004;the second group included T1 and T2 from 2009,which were statistically very different from S1 and S2;while the last two groups were T3 and T4.The structure of the macrobenthic community in T4 was very similar to that in S3.T3,on the other hand,was subjected to frequent human disturbance generating a greater level of habital heterogeneity. Reclamation is an important factor of changing macrobenthic communities.In this study,the composition of dominant species changed markedly with a clear decline in species diversity(Shannon-Weiner index,Pielou′s evenness index,species richness and Simpson′s diversity index).The lowest diversity index was recorded in the reclaimed area.Reclamation on tidal flats changes salinity,tidal action and tidal flat sediment characteristics and dynamics.Human activities have a major impact on zoobenthos communities.Ecological restoration following reclamation projects is essential and may include building water gates,or restocking with macrobenthos and native plant species that can adjust and survive in the new environment.