The invention discloses a large-scale preparation method of niobium pentoxide nanowires and a hydrogen-sensitive element thereof. The preparation method particularly comprises the following steps of: strictly cleaning Nb foils cut into suitable sizes, arranging the foils in a vacuum tube type furnace after a bending or folding treatment, and strictly controlling processing conditions (such as Ar flow rate, O2 flow rate, holding temperature, time and the like) of a thermal oxidation process to synthesize large-scale Nb2O5 nanowires with higher length diameter ratios. By adopting the large-scale preparation method disclosed by the invention, the large-scale synthesis of the Nb2O5 nanowires with the higher length diameter ratios can be realized in a limited-volume furnace tube, thus the production cost can be effectively reduced. Hydrogen-sensitive elements manufactured from Pt electrodes, prepared by sputtering Nb2O5 nanowires as sensitive materials, have the characteristics of small size, low energy consumption and the like, and represent higher response speed and higher sensitivity at the room temperature towards a hydrogen-containing atmosphere; and the size, the energy consumption and the production cost of hydrogen sensors can be hopefully reduced.