Abstract: Concentrations of 7 heavy metals (Zn, Cu, Cd, Pb, Hg, As and Cr) from 33 surface sediment samples in Zhoushan sea area were determined to study their distribution, possible sources and potential ecological risks.The results showed that the concentrations of the heavy metals in the surface sediments exhibited great differences.The distribution of heavy metals decreased gradually from the west to the east, and from the offshore to the open sea.Some regions had very high concentrations.Zn, Cu, Pb, Hg, As and Cr mainly originated from Qiantangjiang River, Yongjiang River coastal industrial or agricultural production and land-sourced pollutants, and there might be a special transformation of Cd in different environmental medium.The results of potential ecological risk assessment showed that Cd and Hg were the main potential risk factors in the study area, and the high values mainly appeared at the Hangzhou Bay estuary, Zhongjieshan archipelago and Changbai-Xiushan sea area.