This study investigated a potential method for the removal of arsenic from enargite leach solution containing 5.86 g/L As(V) by precipitation of magnesium ammonium arsenate (MAA). The experimental results showed the As(V) concentration can be reduced to 1.8 mg/L under the optimum conditions. The molar ratio NH4/Mg/As in precipitates formed at different pH values was checked by wet chemical analysis, indicating that some of by-products such as Mg-3(AsO4)(2), Mg(OH)(2), and MgHAsO4 will be formed at the solution pH above or below pH 9.5. Notably, this study indicated MAA has a better ability for arsenic removal than magnesium arsenate. The precipitates also were characterized by XRD and SEM.