1. The present work is to make a standing crops of aquatic insects in the main stream of the Yeong-san River including its upper streams; the Go-su, the Hwang-yong, the Ji-suk and the Gwang-ju. Investigations were carriedout four times; October 26, ` 72 ; May 26-27, ` 73 and June 2, ` 73. 2. Seven separate station were selected, and collected two fold in each station. 3. 6 Orders and 42 Species wereidentified: Ephemeroptera: 26 spp., Odonata: 1 spp., Plecoptera: 3 spp., Trichoptera: 6 spp., Coleoptera: 3 spp. and Diptera: 3 spp. 4. The Standing crops of aquatic insects of the Yeong-san River were shown in Table 2. The results were as follows; 1) The individual numbers were ranged from 22 to 408. 2) Total weight was ranged from 41.6mg to 6,021.4mg. 5. Mataeopsephenus japonicus and Hydropsyche sp. KA were dominant species in all the stations. 6. Of all standing crops in 7 stations, Coleoptera. has the greatest value.