1. March 19, 1967 to August 31, 1967, the standing crops of the aquatic insects communities and the investigation of all kinds at investigation at 7 stations in the river Kwangnung and the branch of the Han River were investigated. 2. Trichorptera, Ephemeroptera, and Diptera were ranged in all the 7 stations, Plecoptera and other orders were spread in the limited places only. 3. The most standing crops of them were Tricoptera and they amounted to wt. 48.7% and to half of them all. 4. The dominent species, Hydropsyche Ulmer were no. 26.6 and wt 33.6mg. 5. In the investigation of all species, 88 species were discriminated.