To develop a treatment process for treatment of biological nitrogen and phosphorus in constructed wetland using a natural purification system, the applicability of dPAO(Denitrifying Phosphorus Accumulation Organism) for a natural purification system was investigated in the batch experiment. The differences between the PAO(Phosphorus Accumulation Organism) and the dPAO were examined and compared to investigate the applicability of a simultaneous treatment process for biological nitrogen and phosphorus to a sewage treatment plant with a natural purification system using the dPAO in the batch experiment. The COD gradually decreased according to the processing time elapse under the aerobic condition, but there were no differences in the content of NO3-N. In the case of the dPAO, there was no difference in the COD under the anoxic condition, but the content of NO3-N gradually decreased. The content of PO4-P increased according to the increase in the processing time elapse under the anaerobic condition in the case of the PAO and dPAO, and the content decreased according to the increase in the processing time elapse under the aerobic condition in the case of the PAO. In addition, the content decreased according to the increase in the processing time elapse under the anoxic condition in the case of the dPAO as a similar manner as the PAO. Thus, the PAO and dPAO extracted phosphorus under the anaerobic condition. Moreover, it can be seen that the phosphorus absorbed under the aerobic and anoxic conditions. In the case of the dPAO applied in the anoxic condition, the amount of NO3-N treatment was about 1.2mgNO3-N/gVSS after 6 hours of treatment, the PO4-P adsorption was 0.8mgNO3-N/gVSS after 6 hours. In addition, the fraction of the dPAO among the PAO by applying the adsorption amount of PO4-P was about 60%. In addition, it is evident that there are many poly-P with bright yellow fluorescent colors after 6 hours under the anoxic and aerobic conditions from the measurement of the degree of phosphorus accumulation in a microorganism using a fluorescence microscope after dyeing it with DAPI in order to investigate the phosphorus accumulation characteristics of the PAO and dPAO. From the results, it can be verified that the luxury uptake of phosphorus was possible using NO3-N as an electron receptor in an anoxic condition in the case of the dPAO. Thus, it seemed that a simultaneous process of nitrogen and phosphorus will be possible if the dPAO is to be used. Key words : Biological Nitrogen and Phosphorus, PAO, dPAO, DAPI, Poly-P.