Abstract: The concentrations of 8 heavy metals (Cu, Zn, Cr, Pb, Ni, As, Cd and Hg) were analyzed and the potential ecological risks were evaluated to investigate polluting characteristics of heavy metals in coastal sediments of northern Zhejiang. The results demonstrated that the total concentrations of Cu, Zn, Cr, Ni, Pb, As and Hg(except s112)did not exceed class 1 of the marine sediment quality, Cd was at class 3 of the marine sediment quality in 68.8% of the detected sites. The concetrations of Cu, Zn, Ni and As manifested a decreasing trend from nearshore to offshore (p < 0.01). The main sources of Cu, Zn, Cr, Ni, and As were probably industry, agriculture and domestic wastewater, and Pb and Cd mainly came from traffic, mariculture and industrial pollution. The pollution ranks of heavy metals in sediments by geo-accumulation index (I_geo) followed the order:Cd > Ni > Cu > Hg > Cr > Zn > Pb > As, and only Cd was found to be rank 2(Moderately polluted) or above in all detected sites. The results of the potential ecological risk factors (E_rⁱ) illustrated that Hg was disastrous risk at 3.1% of sampling sites, Cd was at rank 3(considerable risk) even higher in all detected stations. The ratio of considerable risk was 21.87% in coastal sediments of northern Zhejiang, the most of potential ecological risk index (RI) were contributed by Cd, accounting for 84.71%.