The acclimation of microorganisms responsible for phosphorus removal consisting of PAO and DPB was investigated by using two (enhanced biological phosphorus removal) EBPR reactors running anaerobic/aerobic (RAO) and anaerobic/anoxic (RAA) respectively to demonstrate the applicability of EBPR to wastewater treatment at low temperature. The results have shown that, at the temperature of 8~11 ℃, phosphorus removal microorganisms (Accumulibacter) have been completely enriched in both anaerobic/aerobic and anaerobic/anoxic reactors after 40 and 80 days of operation, respectively. It has been found that the capacities of phosphorus release and uptake by PAO are higher than that by DPB, presenting the ratios of phosphorus release to MLVSS and phosphorus uptake to MLVSS of 27.7 mg P/g MLVSS, 35.2 mg P/g MLVSS in RAO and 17.4 mg P/g MLVSS, 23.1 mg P/g MLVSS in RAA, respectively. Moreover, DPB can immediately use oxygen as the electron acceptor for uptake phosphorus when given an aerobic condition, while PAO does not rapidly use nitrate as the electron acceptor when given an anoxic environment with the phosphorus uptake per MLVSS of 6.9 mg P/g MLVSS only accounting for 19.6% of that in aerobic condition. Fluorescence in situ hybridization (FISH) analyses has shown that PAO (79.3% of all bacteria) and DPB (61.6% of all bacteria) are dominant in their respective reactors, significantly greater than that in seed sludge (9.3% of all bacteria), which also demonstrates that microorganisms responsible for phosphorus removal have been effectively enriched in the two EBPR systems proposed.