Abstract: Dissolved Cu, Pb, Zn and Cd in the Haikou Bay waters were measured to be respectively in the range concentrations of 0.47～1.16 μg/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 stalions near the Longkun Road Outfall for domestic sewage, the Xiuying Outfall for industry waste water and 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 those 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 particles show that particulate matters in the Haikou Bay seawater play a role in purifying heavy metals. The study on strong complexed form and non-Gable form of dissolved copper shows that the ratio of strong complexed form and dissolved form is about 85%,and non-Gable formic very low with a value lower than 5nmol/dm³. Therefore, copper in the Haikou Bay seawater can not cause influence on marine organisms.