This study aimed to investigate the effect of different anaerobic time(3.5, 3, 2, 1.5h) on the nutrient removal and the intracellular carbon storage of simultaneous nitrification-denitrification and phosphorus removal (SNDPR) systems treating urban sewage. The SNDPR system was enriched with phosphorus accumulating organisms (PAOs) and operated under extended anaerobic (3h) and short low aerobic (2.5h, with dissolved oxygen concentration for 0.5~1.0mg/L). Experiment results showed that the system nitrogen and phosphorus removal perforamce improved with the extending anaerobic time. When the anaerobic time was 3h, the phosphorus release was best with the effluent concentration (0.35mg/L). When anaerobic time gradually increased from 1.5h to 3.5h, poly-hydroxyalkanoates (PHAs) synthetic amount increased, but phosphorus release amount decreased. The results indicated that extended anaerobic time (3h) was benifical for enhacing the intracellular carbon storage, but overlong anaerobic time (above 3.5h) was inimical to the dominant PAOs. Additionally, non-filamentous bulking appeared at the anaerobic time of 1.5h and 2h after 51cycles operation, and pH could be used as the indicating parameter for phosphorus realse, phosphorus uptake and simultaneous nitrification-denitrification in the SNDPR system.