The performance of phosphorus removal with a sequencing batch reactor was investigated by simulated municipal wastewater. The experimental results showed that phosphorus removal could be achieved in sequencing batch reactor without anaerobic phase, which was conventionally considered as a key phase for phosphorus removal. Phosphorus concentration in the effluent was 1.0 mg x L(-1) below after 4 h aeration, during which pH was 7.0 +/- 0.2. Which indicated the removal rate of phosphorus was above 90% when the COD and phosphorus concentrationof influent were about 400 mg x L(-1), 15-20 mg x L(-1), respectively. Intracellular storage of poly-phosphate (poly-P) was increasing in the aeration after decreasing in first hour aeration (the content of poly-P was 83.034 mg x g(-1) at the beginning of aerobic phase, 79.980 mg x g(-1) in first aeration and 83.086 mg x g(-1) in end), but the energy storage poly-beta-hydroxyalkanoates (PHA) was constant nearly and the content was very low (PHA concentration was about 5 mg x L(-1)). The researches indicated that phosphate could be transformed to poly-P by poly-phosphate-accumulating organisms without anaerobic zone and PHA, biological phosphorus removal was obtained by removing sludge with rich phosphorus, and this phenomenon could not be explained by conventional theory.