A new method for the synthesis of powder using a corrosion reaction of metal in alcohol is proposed. Manganese has been dissolved in anhydrous methanol solvent containing ferric chloride as a catalyst by refluxing at 348 K for a period of 7.2 ks. A greenish-black precipitate has been obtained by adding the hydrated solution into NaOH solution at pH 12. This precipitated powder was identified as a manganese ferrite of MnFe₂O₄ by XRD analysis and showed characteristics of a soft ferrite by measuring a magnetic hysteresis loop. SEM observation and measurement of particle size distribution revealed that the powders were coagulation of submicron meter size particles. The preparation of MnFe₂O₄ was explained as mixed corrosion products of manganese with ferric hydroxide derived from addition of FeCl₃.