The invention discloses a synthetic method of lump alpha- ferric oxide nanometer structure, which comprises the following steps: making ferric chloride (FeCl3.6H2O), L- arginine (C6H14N4O2) as raw material; allocating ferric chloride and L- arginine water solution as reacting start liquid under room temperature; placing into rustless steel autoclave lining a politef; heating under 150-180 deg.c at 10-48 h; getting the product. This product use biomolecule--L-arginine as one of raw material, which possesses super material property and simple method.