In ttlis study, the authors used the aquatic insects in the three oders of Mayfly (Ephemeroptera), the Stonfly (Plecoptera) and the Caddisfly (Trichoptera) as bioindicators to assess surface water quality at 05 points in the Ta Lu stream, Nam Dong district, Thua Thien Hue province. The results of analysis of specimens collected they have identified 15 families belonging to 3 oders insect. Data analysis is showed that the biotic indices (EPT) ranging from 2.28 to 3.67, quality of surface water are from quite fresh water to fresh water. All of them can use to purpose for living, for industry branches. agriculture and entertainment. When contract With result of w
:tter environmental analysis by chemical method, the authors find down that water environmental quality determining by biological method give similar result with result by chemical method.