The benthic macroinvertebrate 110 species, 8 classes in 5 Phyla occurred in Keumho river on October, 1990 to March, 1992 (Planaria 1, Nematoda 2, Oligochaeta 3, Hirudinea 11, Gastropoda 9, Pelecypoda 5, Crustacea 2, Insecta 77 species). Species frequency numbers were very different according to survey sites from 60 in upper zone to 11 at lower zone. Taxa with high species frequency were Insecta except Diptera at upper zone, Hirudinea at middle, and Diptera and Oligochaeta at lower zone. Species frequency of Ephemeroptera and Trichoptera on October and November in 1990 increased compared to that of same period in 1990. Mean abundance in this river was 424 Inds./(0.5m^2 as annual level, and Ephemeroptera occupy 29.5%, Diptera 24.5%, Annelida 23.0%, and Crustacea 13.8%. Abundances were variant from 820 Inds./0.5m^2 at site 12 (Tonghwa stream) to 38 Inds./0.5 m^2 at site 16(lowest site in main branch). Dominant taxa were Serratella rufa at Site 1 and Site 12, Baetis nla at Site 2 and Site 3 (Shillyong stream), Asellus hilgendorfi at Site 4 and Site 5, Limnodrilus socialis at Site 9 (Namcheon stream) and Site 14, Chironomus at Site 10, Site 11 and Site 13. Abundances of Oligochaeta and Asellus hilgendorfi decreased after April in 1991 and June in 1991 respectively, but that of Ephemeroptera, Trichoptera, and Pelecypoda increased after September in 1991, but other taxa were not variant seasonally. In Spearman correlation based on abundance, Limnodrilus socialis and Chironomus showed negative relation with other taxa, Caenis KUa and Baetis nla showed high positive correlation each other. In Bray-Curtis polar ordination with percent dissimilarity based on species frequency, Hydropsyche and Cheumatopsyche seem to be a little intolerant taxa, and Ecdyonurus yoshidae and Serratella rufa - a little tolerant taxa -, Glossiphoniidae, Erpobdelliidae, Asellus hilgendorfi, Caenis KUa, and Baetis nla -tolerant taxa -, Limnodrilus socialis and Chironomus - very tolerant taxa -. One cluster appeared by group mean and unweighted pair-grouping with SØrensen`s similarity coefficient among sites. Clustered sites were more or less clean and not-clustered sites (Site 9, 10, 11, 14, 16) were severely polluted.