Low-valent vanadium oxide nanostructures have been synthesized in large quantities using commercial V2O5 powder as the precursor by a facile reduction method. The crystal structures and morphologies of vanadium oxide nanostructures can be adjusted by altering the concentrations and types of reductants. VO2(B) nanostructures are fabricated using oxalic acid as the reductant. VO2(B) nanobelts with widths of 80-150 nm, thicknesses of 20-30 nm, and lengths up to several micrometers can evolve to olive-like nanostructures composed of nanosheets with thicknesses of several nanometers and lateral dimensions of several micrometers as the concentration of oxalic acid increases. H2V3O8 nanobelts with widths of 200-300 nm, thicknesses of 10-20 nm, and lengths up to several 10s of micrometers are obtained under the reduction of V2O5 powder with ethanol. The belt-shaped morphologies of H2V3O8 are not affected by the concentration of ethanol.