The benthic macroinvertebrates in the Hwangryong river occurred 51 species, 42 genera, 26 families, 10 orders, 5 classes in 3 phyla. Among them, aquatic insects containing 44 species were the major group comparing 84.6% of the whole. In particular, a great many Ephemeroptera containing 17 species occurred and Megaloptera were found only in 2 species. Also, there were 4 species of Trichoptera. The comparison of species at each site revealed the largest number of 29 species at site 2 and 3 respectivly, and the smallest was 18 species at site 1. The seasonal number of collected species were similar, as followers; 30 species occurred in winter, 25 species in spring, 28 species in summer, and 22 species in autumn. On comparing individual numbers in this survey, Ephemeroptera were the highest (50%) and Trichoptera were 37%. The most dominant species belonged to Trichoptera and Ephemeroptera. Above all, Uracanthella rufa and Cheumatopsyche brevilineata were dominant. Dominant indices ranged from 0.46 to 0.94. Species diversity indices ranged from 1.04 to 3.00. According to the saprobic system based on the species diversity indices of benthic macroinvertebrates, water quality was β-mesosaprobic in each site. The biological water quality as biotic indices was evaluated from α- to β-mesosaprobic, the pollution indices evaluated β-mesosaprobics, the simple water quality evaluation revealed secondary water quality criteria and the GPI evaluated ranged from oligosaprobics to β-mesosaprobics. The biological water quality evaluation by these indices proved similar to the results of chemical analysis.