In this paper, the diffusion behavior between MgO and Fe_2O_3(the main iron oxide in pellets) is investigated using a diffusion couple method. In addition, the distribution regulation of MgO in MgO-bearing pellets is analyzed via pelletizing experiments. The results illustrate that MgO is prone to diffuse into Fe_2O_3 in the form of solid solution; the diffusion rate considered here is 13.64 μm·min~(-1). Most MgO content distributes in the iron phase instead of the slag phase. The MF phase {(Mg_(1-x)Fe_x)O·Fe_2O_3, x ≤ 1} is generated in the MgO-bearing pellets. However, the distribution of MgO in the radial direction of the pellets is inconsistent. The solid solution portion of MgO in the MF phase is larger in the outer layer of the pellets than in the inner layer. In this work, the approximate chemical composition of the MF phase in the outer layer of the pellets is {(Mg_(0.35-0.77)·Fe_(0.65-0.23)) O·Fe_2O_3} and in the inner layer is {(Mg_(0.13-0.45)·Fe_(0.87-0.55))O·Fe_2O_3}. In this paper, the diffusion behavior between MgO and Fe_2O_3 (the main iron oxide in pellets) is investigated using a diffusion couple method. In addition, the distribution regulation of MgO in MgO-bearing pellets is analyzed via pelletizing experiments. MgO is prone to diffuse into Fe 2 O 3 in the form of solid solution; the diffusion rate considered here is 13.64 μm · min -1. Most MgO content distributes in the iron phase instead of the slag phase. The MF phase {Mg_ (1-x) Fe_x) O · Fe_2O_3, x≤1} is generated in the MgO-bearing pellets. However, the distribution of MgO in the radial direction of the pellets is inconsistent. The solid solution portion of MgO in the MF phase In this work, the approximate chemical composition of the MF phase in the outer layer of the pellets is {(Mg_ (0.35-0.77) Fe_ (0.65-0.23) ) O · Fe 2 O 3} and in the inner layer is {(Mg_ (0.13-0.45) · Fe_ (0.87-0.55)) O · Fe 2 O_ 3}.