Abstract: In order to investigate the geochemical patterns of heavy metals (HMs) and their potential ecological risks in the coastal area of Guangxi, this study examined the patterns of eight HMs (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in the surface sediments of typical bays of this region. The modified three-step sequential extraction method was used to extract the fractions of HMs, and the relationships between HM fractions and physicochemical properties were analyzed. The ratio of secondary phase to primary phase (RSP) method and risk assessment code (RAC) method were calculated based on the available forms of HM content, and then the potential ecological risk of surface sediments was assessed. The results showed that weak acid extractable fractions of Cd (62.37%) was the most abundant in surface sediments from the near-shore bays in Guangxi, followed by reducible fractions of Pb (46.04%) and oxidizable fractions of Hg (49.79%). Conversely, As (88.90%), Cr (63.82%), Cu (52.05%), Ni (52.90%), and Zn (43.65%) were mainly in a stable residual state, with good stability. Weak acid extractable fractions of Cu, Ni, Pb, and Zn are easily released in an environment rich in nitrogen, phosphorus, and total organic carbon. Bioavailable Cu, Ni, and Pb are readily combined with clay sediments, while the pH value has little effect on the release of each HM fraction. The RAC values of Zn and Ni were 17.16% and 12.11%, respectively, indicating low risk. The RSP value and RAC value of Cd were 8.24 and 62.37%, respectively, indicating severe pollution and high risk. Accordingly, prioritized preventive and control measures are warranted to mitigate the serious threat.