Abstract: An indoor experiment using undisturbed soil columns from Baiyangdian Lake was carried out to elucidate the purification dynamics of total phosphorus (TP) in a reed growing system and to estimate the environmental capacity of TP. Compared with the control, the reed biomass in duck wasterwater increased by 36.1%, 24.4%, and 24.3%, in the low, medium, and high concentrations respectively of TP. By using the reed wetland system, the TP removal from the duck wastewater was very obvious at different time periods and the removal efficiency reached up to 98%. The purification process of TP tended to decline when the hydraulic retention time was over 3 days. The TP purification of this ecosystem in different periods fitted a power function equation and the best purification efficiency was achieved when the temperature was 23℃. It showed that the best removal effect associated with the shortest hydraulic retention time and the smallest area may be achieved when this system is used to purify high P wastewater and thus ane environmental capacity of 171.71 t/a for TP was calculated.