Abstract: We explored the effects of carbon supplementary modes on operational performance in a tidal flow constructed wetland (TFCW) utilizing phosphorus bioaccumulation/phosphorus harvesting (PB-PH) process. Three different carbon supplementary modes were adopted during the periodical phosphorus harvesting process. The results showed that the carbon supplementary mode significantly affected the performances of phosphorus bioaccumulation and phosphorus harvesting throughout the experiment. The optimization of carbon supplementary mode would facilitate the maintenance of abundance and activities of polyphosphate-accumulating organisms (PAOs). Subsequently, the amounts of phosphorus release and PHB synthesis in PAOs, as well as the utilization rate of supplementary carbon, could be effectively enhanced during the phosphorus harvesting process. The efficient and stable phosphorus removal effects of the TFCW could be ensured during the phosphorus bioaccumulation process. When the PB-PH cycle length was 30 d and using the continuous circulation carbon supplementary mode, the amount of phosphorus retained in the bed and the mean phosphorus harvesting efficiency of the TFCW were 26994.88 mg and 70.8%, respectively. Regarding a typical PB-PH cycle, the mean phosphorus removal efficiency of the TFCW could achieve (91.4±2.1)% during the phosphorus bioaccumulation process. The amounts of phosphorus release and PHB synthesis in PAOs, and the utilization rate of supplementary carbon in the system could reach up to (1563.72±127.84) mg, (4.52±0.39) mmol C·g^-1 VSS, and (97.3±1.6)%, respectively.