Three groups, zooplanton, phytoplanton, and macrobenthos, were collected to assess the water quality in the confluence of Nhue-Day rivers in Ha Nam province from 2012 to 2013. The authors recorded 87 species of phytoplanton, 42 species of zooplanton, and 50 species of macrobenthos from study area. Most of them are common or widespread species in Vietnam. In this study, the authors also identified many species, that can be used to assess the organic pollution of water, for example as the members of Eugfena, Osciffatoria, Scenedesmus, Chloreffa, Nitzschia (phytoplanton) and Rotatoria and Cafanoida (zooplanton), as well as some species of macrobenthos. Biodiversity indices (H and D) showed that the water quality in the confluence of Nhue-Day rivers were polluted from low to high levels.