Abstract: Based on the analyses of phytoplankton community in the treated and untreated reaches of Suining tributary of Suzhou River,this paper studied the effects of bio-remediation on phytoplankton.As the result of the remediation,the density and Chla content of phytoplankton in treated reach were greatly declined,while the species number and Shannon-Wiener diversity index ascended obviously.The percentage of Chlorophyta and Baeillariophyta ascended,and some species indicating medium-and oligo-pollution were found.All of these illustrated that bio-remediation engineering might significantly benefit to the improvement of phytoplankton community structure and water quality.

Key words: Intertidal zone, Community diversity, Community, Changshan archipelago