We have succeeded to synthesize the octahedral micro shape of MnFe2O4 through the co-precipation process followed by a ceramic processing method. At the beginning, the Mn3O4 and Fe2O3 nanoparticles were separately synthesized by the co-precipitation method from the low grade manganese ore and iron sand, respectively. Here, effect of the weight ratio of Fe2O3 and Mn3O4 to the crystal and microstructure of MnFe2O4 were investigated. Four cases of weight ratio i.e. 60:40, 70:30, 80:20, and 90:10 were considered. After mixing and compaction process in the cylindrical mould shape, the samples were sintered at 1000 °C and for 6 hours. XRD data showed that a high quality crystal phase of MnFe2O4 can be obtained for both mass ratio of 60:40 and 70:30, while in the case of 80:20 and 90:10 the MnFe2O4 appear together with impurity of α-Fe2O3. The particle shapes are almost octahedral in the micrometer size in the range of 1.2 to 1.5 m. The magnetic property shows a soft-magnetic type with a 27.5 emu/g of saturated magnetization. This will be potential for applications as the electrode materials and the magnetic core.