Assessment of sediment heavy metal pollution and potential ecological risk in a drinking reservoir is crucial for water quality security and human health. Six heavy metal (Cr, Cu, Ni, Pb, Zn, and Cd) contents in the surface sediments of Hongfeng Lake were measured. The results showed that Pb and Zn were the main heavy metal pollutants at Hongfeng Lake. The distribution of the heavy metals in the surface sediments varied spatially, and the contents of heavy metals in the northern lake area were significantly higher than those in the southern area. Heavy metal contents at Hongfeng Lake may be related to river inputs, atmospheric deposition, infiltration, and runoff inputs in the watershed. The correlations between Cr, Cu, Ni, Pb, and Zn contents were significant, which may indicate that they may have the same sources. The single factor ecological risk index showed that the six heavy metals in the surface sediments had low potential ecological risk, which was consistent with the result assessed by the comprehensive potential ecological risk index.