Abstract: Heavy metal concentrations in sediments are important factors reflecting the environmental quality of coastal zones, thus the exploration of those in Haikou Bay is of great significance to the sustainable development of coastal area utilization. Surface sediment samples in Haikou Bay and adjacent region were collected in March 2018. The spatial distributions and geochemical characteristics of particle size, organic carbon (OC) and seven heavy metals (Cu, Pb, Zn, Cd, Cr, Hg and As) of the surface sediments were investigated. The results showed that the average content of Cu, Pb, Zn, Cd, Cr, Hg and As in the surface sediments was 14.1, 27.1, 63.7, 0.06, 41.5, 0.050 and 12.79 mg/kg, respectively. Positive correlation was observed between the contents of Cu, Pb, Zn, Hg and OC, respectively. Cu, Pb, Zn, Cr tend to be enriched in fine-grained sediment and the distribution of Cd and Hg was mainly controlled by the pollution from point sources such as rivers, industrial and urban sewage discharges. In contrast, the distribution of Cr and As was little affected by those discharge processes. The evaluation of geoaccumulation index indicated the heavy metals in surface sediments were unpolluted, while Hg and As were mild polluted in Haikou Bay. The degrees of Håkanson’s potential ecological risk for the seven heavy metals were followed the order: Hg>Cd>As>Pb>Cu>Cr>Zn. As a whole, the assessment results showed that the potential ecological risk of the heavy metals in surface sediments were at a moderate level.