The invention mainly belongs to the field of photoelectrochemistry water-splitting for hydrogen production and particularly relates to a vanadium-doped ZnO nanorod array photo-anode, a preparation method of the vanadium-doped ZnO nanorod array photo-anode and an application of the vanadium-doped ZnO nanorod array photo-anode in photoelectrochemistry water-splitting for hydrogen production. The method comprises the steps of preparing a ZnO seed crystal solution, a vanadium-doped solution and a growth solution correspondingly; conducting spin-coating on conducting glass with the ZnO seed crystal solution and obtaining the conducting glass with the surface covered with a ZnO seed crystal layer after spin-coating and annealing; pulling the conducting glass with the surface covered with the ZnO seed crystal layer into a mixed solution of the vanadium-doped solution and the growth solution for a hydrothermal reaction, washing the conducting glass with deionized water after completion of the reaction, conducting annealing in a muffle furnace and then obtaining an vanadium-doped ZnO nanorod array. By adopting the vanadium-doped ZnO nanorod array photo-anode provided by the invention, the carrier life is prolonged, combination of electron holes is reduced, and the photoelectrochemistry water-splitting performance is improved.