Abstract: From October 1999 to July 2001,this study investigated the effects of dredging on the community and structure of the micro-invertebrate in Huangdu and Huacao on headwaters of Suzhou creek. The result was that Mollusca and Oligochaeta were dominant in the both sites.Before dredging, there were six species of Mollusca,tree species of Oligochaeta and one of Hirudinea in Huangdu, and one Mollusca and four Oligochaetas in Huacao. After dredging,more species of invertebrate were found. In Huangdu,there was one species more than before, and in Huacao, there were four species more than before.So the recovery of the species in Huacao is more obvious. Dredging removed the density and biomass of the community, but the diversity of the community was increasing graduallu in one year. Furthermore, exponentisl of diversity of dredged was always higher than before in Huacao.But in Huangdu, it wasn't higher than before until half year later. It is suggested that dredging in headwaters of Suzhou creek help for the recovery of the community of micro-invertebrate.

Key words: dredging, exponential of diversity, density and biomass, Suzhou creek, invertebrate, dredging, exponential of diversity, density and biomass, Suzhou creek