The effect of CaCO_3, Na_2CO_3, and CaF_2 on the reduction roasting and magnetic separation of high-phosphorus iron ore containing phosphorus in the form of Fe_3PO7 and apatite was investigated. The results revealed that Na_2CO_3 had the most significant effect on iron recovery and dephosphorization, followed by CaCO_3, the effect of CaF_2 was negligible. The mechanisms of CaCO_3, Na_2CO_3, and CaF_2 were investigated using X-ray diffraction(XRD), scanning electron microscopy and energy dispersive spectrometry(SEM–EDS). Without additives,Fe_3PO_7 was reduced to elemental phosphorus and formed an iron–phosphorus alloy with metallic iron. The addition of CaCO_3 reacted with Fe_3PO_7 to generate an enormous amount of Ca_3(PO_4)_2 and promoted the reduction of iron oxides. However, the growth of iron particles was inhibited. With the addition of Na_2CO_3, the phosphorus in Fe_3PO_7 migrated to nepheline and Na_2CO_3 improved the reduction of iron oxides and growth of iron particles. Therefore, the recovery of iron and the separation of iron and phosphorus were the best. In contrast, CaF_2 reacted with Fe_3PO_7 to form fine Ca_3(PO_4)_2 particles scattered around the iron particles, making the separation of iron and phosphorus difficult.