Neutralization precipitation process is often used to remove impurities such as iron, aluminum and chromium from the nickel laterite acid leach solution, however, it accompanied with the loss of nickel and magnesium metal ions. The precipitation behaviors of Ni2+ and Mg2+ ions in nickel laterite acid leach solution during the neutralization precipitation iron removal process was deeply discussed in this work. Furthermore, a novel precipitation mechanism of Ni2+ and Mg2+ with SO42- during the neutralization precipitation iron removal process was proposed. The results showed that under the condition of fixed Ni2+ and Mg2+ concentrations in simulated leachate, the loss rate of Ni2+ and Mg2+ during neutralization and precipitation respectively were 9.13%~23.23% and 9.79%~15.68% with the increase of Fe3+ concentration in simulated leachate. Under the condition of fixed Fe3+ concentrations, the loss rate of Ni2+ and Mg2+ decreased with the increase of the concentration of Ni2+ and Mg2+. According to the results of solution chemical calculation and the characterization of iron hydroxide precipitation by infrared spectroscopy and scanning electron microscopy, both SO42- ions and Fe(OH)3 colloids could co-precipitate in the form of monovalent or binary complex during the neutralization process, in which the lone pair electrons of SO42- in the monovalent complexes bond with Ni2+ and Mg2+ and adsorb, resulting Ni2+ and Mg2+ in the leachate were co-adsorbed with SO42- by Fe(OH)3 colloid and the loss was caused. In addition, it was found that the surfactant such as cetyl trimethylammonium bromide (CTAB), polyethylene glycol (PEG), sodium dodecyl benzenesulfonatecan (SDBS) was added during the neutralization precipitation process can effectively compete for adsorption with neutralizing precipitated products or impede the combination of SO〖_4^(2-)〗 with Ni2+ and Mg2+ ions, which could enhance the selective precipitation of Fe3+ ions during neutralization process. When the dosage of three surfactants was 2×10-5 mol/L, the retention rates of Ni2+ in the process of neutralization and precipitation of iron could reach about 95%, and Mg2+ could reach 100%.