Abstract: From August to September 2018, the distribution of 7 kinds of heavy metals in the sediment samples collected at 25 stations in Hangzhou bay was studied. The results showed that the average concentrations of Cu, Pb, Zn, Cd, Cr, Hg and As in the surface sediment were 22.50, 21.93, 63.39, 0.10, 48.32, 0.05 and 5.45×10⁻⁶, respectively. The average concentrations of all the evaluation factors were lower than the background values of heavy metals in the national coastal zone. According to the evaluated result by the single factor pollution index method of marine sediment quality, all the average contents of Cu, Pb, Zn, Cd, Cr, Hg and As were in the line with the class I standard of marine sediment quality. The pollution degree of the average contents of 7 kinds of heavy metals was Cu > Cr > Zn > Pb > As > Hg > Cd. According to the analysis result of heavy metal enrichment degree, the enrichment degree of Cd, Hg and As was relatively lower, and the enrichment degree of Pb and Zn was relatively higher. According to the evaluation result of potential ecological hazard index, the potential ecological risk index of Hangzhou bay was "low" and the marine ecological environment was in the good condition. The correlation analysis of heavy metals and TOC in the surface sediments showed that the TOC content in the surface sediments of the bay was positively correlated with the contents of heavy metals Cu, Pb, Zn, Cd and Cr. Based on the principal component analysis, the sources of heavy metal pollution in the sediments were further studied, and the contribution rates of the first two principal components were 64.42% and 16.59%, respectively. Combined with the correlation analysis, it was found that the main sources of heavy metal Cu, Pb, Zn, Cd and Cr were the pollution of industrial production and domestic sewage to marine sediments.