Abstract: The contents of total copper,dissolved copper and free copper in the samples obtained in the estuary of the Pearl river were analyzed.It was found that the mass concentrations of total copper increased from the estuary to the open sea,which is not necessarily consistent with the rule of land-source rule.It could be concluded that,besides the run-off from the river,there should be other sources of copper to the estuary of the Pearl river;and the coastal upwelling affected the copper contents and its specification distribution heavily.However,the distribution rule of free copper is opposite,and either the concentration of free copper ion or the ratio of free copper to total copper decreased with the increase of salinity of water from the esturary to the open sea.In the study,the copper uptake by Dunaliella tertiolecta was also analyzed after cultivating in water samples of different salinity in order to verify the copper specification distribution character in the estuary of the Pearl river through the bioavailability of metal copper to the algae.