The invention relates to a nanometer vanadium oxide and the preparing method thereof, which belongs to the fields of nanometer material and nanometer technology.Under the effects of different templates, through hydrothermal synthesis or renewed arrangement process of fine articles , different vanadium sources generate nanometer vanadium oxides with the shapes of rod-like and irregular flakes or regular round flakes.The length of nanometer rod is 1 to 5Mum and the diameter is 20 to 150nm.The length of the vanadium oxide with the shape of round flake is 0.5-2 Mum and the thickness is 20 to 150nm.The preparing method is characterized by the low material cost, simple process, as well as controllable shape and appearance of the nanometer material, etc., and the same time has important exploitation value and application prospect.