The invention discloses a method for preparing an electrode material for a supercapacitor made from manganese dioxide doped with an iron element, belonging to the technical field of electrochemical science and energy source. The method for preparing the electrode material for the supercapacitor made from the manganese dioxide doped with the iron element is characterized in that manganese chloride, ammonium oxalate and ferric chloride are used as raw materials; and a nano manganese dioxide material doped with the iron element is prepared through low-temperature solid-phase reaction by calcination and acidification methods. The prepared material can be evenly compounded with acetylene black/polytetrafluoroethylene (PTFE); a proper amount of alcohol is added; after being evenly mixed, the material is coated on foamed nickel; and after the drying, an electrode is formed by a hydraulic method. The method for preparing the electrode material for the supercapacitor made from the manganese dioxide doped with the iron element has the advantages that the process flow for preparing the nano manganese dioxide material doped with the iron element is simple, and the prepared electrode has higher specific capacitance.