Community structure of benthic macroinvertebrates in the water system of Anyang Stream was analyzed from August, 2002 to April, 2003. Species number of benthic macroinvertebrates was 78 species, 33 families, 11 orders, 5 classes in 3 phyla. They were collected 49 species at 1st survey, 51 species at End survey and 53 species at 3rd survey, respectively. Species numbers at each tributary were 43 species at the Wanggok Stream, 44 species at the Mokgam Stream, 33 species at the Ohjeon Stream and 26 species at the Hakeu Stream, while it was only 9 species at the Dangjeong Stream. Species number of the main course of Anyang Stream was 24 species. Dominant species of benthic macroinvertebrates at the Wanggok, Ohjeon and Hakeu Stream were Baetis fuscatus, Alainites muticus, Physa acuta and chironominae sp. They were mainly intermediate and tolerant species. Dominant species and subdominant species of the Dangjeong Stream were Limnodrilus socialis, Psychoda KUa and Telmatoscopus KUa as indicator species for severe sewage pollution. Dominant species at Geumjeong-dong and KUa bridge in the main course of Anyang Stream were Physa acuta, Limodrilus gotoi, Chironominae sp., Species diversity indices at the Mokgam Stream were $high(3.53~4.28;range)$ and those of the Hakeu, Wanggok and Ohjeon Stream were some what high$(2.00~3.13;and;2.34~3.10;range)$. But, species diversity indices in the Dangjeon Stream were low$(1.36~1.70;range)$ too. and those of the main course of Anyang Stream were low$(0.86~1.79;range)$ too. Species richness indices in the Wanggok and Mokgam Stream were very high$(3.55~4.02;and;2.96~5.31;range)$ and those of Geumjeong-dong and Kia bridge in the main course of Anyang Stream were low$(0.89~1.98;range)$. Stream bed and riparian bank of middle reach in the Wanggok Stream were good condition and water was clean. The Mokgam Stream had various microhabitats, good water weed area, hetero geneous substrates and etc.. And, stream bed in the Hakeu Stream was in good condition. So, above streams should be continuously in good ecological condition and useful area for citizens.