Abstract: To achieve effectiveness of nitrogen and phosphorus removal, a two-sludge denitrifying phosphorus removal system (A₂N₂) was used to treat low ρ(C)/ρ(N) ratio real domestic wastewater. Based on different influent flows (characterized by influent ratio) and nitrifying fluid return flows(characterized by exchange ratio) conditions, the system achieved efficient denitrifying phosphorus removal performance. The experiment was conducted as follows:anaerobic was set as 1.5 h, anoxic was 2 h, and aerobic was 10 min in the A-SBR unit. First the nitrification duration time was 4 h. Second, the nitrification duration time was 1 h in the N-SBR units. The aeration flow rate of A-SBR and N-SBR units was 100 and 120 L/h, respectively, and the filling rate was 66%. Under this condition, nine different parameters were experimentally tested by varying the influent ratio R₁ (70%, 75%, and 80%) and the exchange ratio of R₂ (70%, 75%, and 80%), respectively. Results show that under the condition of different influent ratios and exchange ratios, the A₂N₂ system can remove COD stably and efficiently. The average COD removal rate in each stage is above 80%. However, the removal performance of TN is significantly different, which is 61.67%-78.3%. When the influent ratio and exchange ratio are 70% and 80%, the TN removal rate of A₂N₂ system is the best, which is 78.3%. The average effluent TN is 9.2 mg/L. In the aspect of phosphorus removal, the exchange ratio increases from 70% to 80% and the denitrifying phosphorus removal rate remains above 99%. The effluent phosphorus concentration is below 0.1 mg/L.