We examined whether several reeds, which are found around Ulsan area, could be used for downflow reed-bed to remove pollutants of sewage. Three kinds of reed, such as Phagmites australis, Typha orientalls, and Phalaris aundinacea L., were collected from their habitats near the Taehwa River in Ulsan City. In the minimized model system of downflow reed-bed, P. australis appeared to reduce BOD more than others did but slightly increase total amount of nitrogen(N). When P. australis were placed in the sterilized water, total nitrogen was found to be significantly increased dependent on the number of experimental plant in the sterilized state, but it was rather decreased in the non-sterilized state. With these results, microorganisms attached to P.australis roots can be thought to work for removal of pollutants. Therefore, these microorganisms and their habitat, P. australis reed bed, together can be used for sewage treatment. It was suggested that oxygen is produced by photosynthesis reaction of P. austrails. The increased oxygen may help microorganisms in their habitats to work on the removal of pollutants