Abstract: The feasibility of the treatment of phosphate wastewater by the magnesium ammonium phosphate (MAP) precipitation process was discussed. Some factors affecting the result of removal of ammonium and phosphate, such as pH, molar ratio, reaction time，stirring speed，precipitation time were discussed. When treating the phosphate wastewater with PO43－- P 1753.46 mg/L by adding MgSO4·7H2O and NH4Cl, the better treatment conditions were as follows：pH=9.5，n(Mg)∶n(P)∶n(N)= 1.4∶1.11∶1.0，stirring speed about 200 r/min, reaction time 20 min. When precipitation time was 30 min, the removal ratio of PO43— was 98.69%. The quantity of PO43—-P in the treated water was 9.16 mg/L. The quantity of NH3-N in the treated water was 64.10 mg/L. Sediment was confirmed by scanning microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS).