The effect of Si addition was studied for the purpose of the improvement of microstructure of MgFe2O4 particles prepared from a malic acid complex. There were no traces of any impurity phase in Si-doped and pure MgFe2O4 powders both in XRD measurements. When Si atoms were doped to MgFe2O4 , crystallite growth of MgFe2O4 was remarkably suppressed, and the lattice volume increased up to 10 mol% Si monotonously. SEM observations revealed that MgFe2O4 powders show a granulation shape such as the aragonite and each particle tightly interconnected each other, whereas smaller particles compared with pure MgFe2O4 were observed for Si-doped MgFe2O4 . Also, it was found that the amount of mesopore increases by Si doping. Further, XPS and XAS measurements suggested that Si atoms exist in MgFe2O4 crystal.