To enhance the simultaneous removal of nitrogen (N) and phosphorus (P) of low C/N (P) ratio sewage by A²/O technique, and ensure the effluent meet the first class level A standard of GB18918—2002, two patterns of A²/O technique were conducted to treat the experimental sewage. Pattern 1 was the A²/O technique with the carrier, under the optimized conditions of tHR=8.2 h, R=80%, r=250%-300%, ρ(DO)=1.5-0.5 mg/L, the concentration of TP in effluent of the system still exceeded the standard. Pattern 2 was the improved pattern 1— terminal intermittent aeration A²/O technique with the carrier, which contained an intermittent aeration zone following the aerobic zone, meanwhile, the approaches of sludge return and discharge were changed. The novel system with the long tSR of 22.3 d ran at the conditions of the optimal operating modes above-mentioned for A²/O zone, tHR=4 h for the intermittent aeration zone, and the aeration cycle was 1 h: aeration time was 1 min (ρ(DO)=0.3-0.5 mg/L) and settling time was 59 min. The operational results showed that the average removal rate of COD, NH₄+-N, TP and TN reached 87.8%, 99.1%, 95.5% and 90.8%, respectively. The nitrosation rate of the effluent was above 70%, and DPAO/PAO ratio in sludge was 95.65%, the final effluent of the system met the first class level A of the national standard through the pathway of shortcut nitrification and denitrifying nitrogen and phosphorus removal.