Abstract: Magnesium Ammonium Phosphate Process was used to treat simulated wastewater that include nitrogen and phosphorus by low-grade light calcined powder. Some factors affecting the removal efficiency of nitrogen and phosphorus were discussed, including pH, N/P ratio, low-grade light calcined powder dosage, reaction time. Results indicated that for Magnesium oxide content of 89% in light calcined powder, when the N/P ratio was 90:300, the opimal dosage was 7 g/L, the pH value was 8, and the reaction time was 25 min, the removal efficiency of nitrogen 98.59% and phosphorus 89.30% can be got. MAP precipitation method by low-grade light calcined powder can effectively recover nitrogen and phosphorus elements in wastewater and there are wide application prospect in resource recycling and environmental protection.