Abstract: 【Objective】Investigate the mechanism of organic carbon(OC), total nitrogen(TN), total phosphorus(TP)and heavy metal(As, Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn)accumulation in sediment of plant communities in river. 【Method】We selected three sites dominated by Scirpus planiculmis and Sparganium stoloniferum each in shoal and shallow water habitats of the Suo River, a tributary of the Huai River. We collected sediment from the surface layer(0-10 cm), middle layer(≥10-20 cm)and sublayer(≥20-30 cm)of the plant communities and CK(blank control). We analyzed the accumulation of OC, TN, TP and heavy metals in the sediment of three layers using t-tests for independent samples; calculated relative enrichment index (E)of OC, TN, TP and heavy metals in the sediment of three layers; and then used partial least squares regression to analyze the influence of various factors on each element’s E.【Result】OC, TN, As, Cd, Cr, Hg, Ni, Pb and Zn were significantly enriched in sediment of the S. planiculmis and S. stoloniferum communities. The enrichment effect mainly occurred in the surface sediment. Overall, the main factors influencing the elements’ E values were the elements’ background values in the sediment, followed by plant species, habitat type, and sediment texture. 【Conclusion】The results of the present study provide a reference for the ecological restoration of polluted rivers. Planting local dominant species in polluted rivers helps transfer carbon, nutrient elements and some heavy metals from the river ecosystem into the sediment of the plant communities, especially into the surface sediment. The main driving forces may be plants’ interception of particulate matter and nutrients in the water, as well as the decomposition and mineralization of plant litter and dead roots. It is also possible that S. planiculmis can absorb Cd, Cr, Hg, Pb and Zn and that S. stoloniferum can absorb As, Cd, Cr, Hg, Ni, Pb and Zn, although this requires validation.