Dissolved Cu, Pb, Zn and Cd in the I-Iaikou Bay waters were measured to be respectively in the range concentrations of 0.47-1.16μg/dm3, 0.94-2.36 μg/dm3, 1.28-4.83 μg/dm3 and 0.005-0.072 μg/dm3; with respectively average values of 0.78 μg/dm3, 1.36 μg/dm3, 3.14 g/dm3 and 0.03 μg/dm3.Dissolved Cu and Zn concentrations are relatively high at the stations near the Longkun Road Outfall for domestic sewage, the Xiuying Out-fall for industry waste water and the Haidian Island Estuary, but dissolved Pb and Cd concentrations are low in these stations.The values in other stations are comparatively homogenous.Vertical dissolved Cu, Pb and Zn concentrations at the bottom layer are higher than at the surface layer, but dissolved Cd concentration appears to be on the opposite.The measurement results of Cu, Pb, Zn and Cd in suspended particle show that particulate matters in the Haikou Bay seeweter play a role in purifying heavy metals.The study on strong complexed form and non-liable form of dissolved copper show that the ratio of strong complexed form and dissolved form is about 85%,and non-liable form is very low with a value lower than 5 nmol/dm3.Therefore, nipper in the I-Iaikou Bay seawater cannot cause influence on marine organisms.