The reversed A2O (anoxic/anaerobic/aerobic) process is efficient in nitrogen removal from domestic wastewater, while phosphorus removal performance needs further optimization. In this study, the effects of influent VFAs/COD and anaerobic duration on anoxic/anaerobic phosphorus release and aerobic phosphorus uptake were investigated in the reversed A2O process. The results indicated that the maximum anoxic P release rate of 37.6 mg P/(L·h) was achieved in synthetic wastewater with influent VFAs/COD of 100%. With increasing VFAs/COD from 15% to 100%, the aerobic phosphorus uptake rate increased by 2.8–3.7 times. Proper extension of the anaerobic duration can marginally enhance the phosphorus uptake rate and aerobic microbial activity, thus resulting in higher phosphorus removal efficiency. As a consequence, the optimal anaerobic duration for domestic wastewater was confirmed to be 4 h. Additionally, there is a significant correlation between phosphorus removal related indicators of substances metabolism and microbial activity in synthetic wastewater. However, poor correlation between the indicators of phosphorus metabolism and microbial activities was observed in domestic wastewater, mainly due to the coexistence of other competitive biological reactions.