Abstract: The concentrations and distribution characteristics of eight heavy metals (Zn, Pb, Cu, Ni, Cd, Cr, Mn and As) were analyzed in fifteen surface sediment samples from Gaozhou Reservoir and its tributaries in South China, in order to comprehensively evaluate pollution levels of heavy metals in the surface sediments and their potential ecological risk in Gaozhou Reservoir (Shigu Reservoir area and Liangde Reservoir area).Heavy metal pollution in the sediments from Gaozhou Reservoir and its tributaries was analyzed and evaluated using geoaccumulation index (I_geo), potential ecological risk index (RI), and Sediment Quality Guideline (SQG), based on effect range low (ERL)/effect range median (ERM) values and threshold effect level (TEL)/probable effect level (PEL) values.The results indicated that the concentrations of heavy metals in the sediments from Gaozhou Reservoir and its tributaries had similar variation trends, with the order of contamination level being Zn>Cr>Pb>Mn>Ni>Cu>As>Cd.The degree of Cd and Cr spatial fluctuation appeared to be higher than other heavy metals in the surface sediments.According to the geoaccumulation index, the pollution degree of heavy metals in the surface sediments from Gaozhou Reservoir and its tributaries ranged from no pollution to moderate pollution, with the order of pollution degree being: Zn>Cd>Cr>Ni>Pb≈Cu >Mn≈As.The potential ecological risk index indicated that the degree of heavy metal pollution in the surface sediments from Gaozhou Reservoir and its tributaries represented moderate ecological harm.The biological acute toxicity effect of heavy metals in the sediments of Gaozhou Reservoir was not obvious, based on two different sets of Sediment Quality Guidelines (ERL/ERM and TEL/PEL).The total toxic units of heavy metals in the surface sediments from the Pengqing River, an upstream tributary of Gaozhou Reservoir, were higher than those of the other sites.The results suggested that attention should be paid to the potential toxic risk of upstream tributaries.