In this study, water and sediment quality and benthic biota at the seven stations between the upper reaches and the lower ones in the River Akagawa were investigated in all seasons during three years. In addition, data on water and sediment quality and benthic macroinvertebrate were statistically treated and the components of water and sediment quality influencing the habitation of benthic macroinvertebrate were extracted by multivariate analyses.