The invention discloses a fluorophosphate quadrangular-prism nano material, and a preparation method and application thereof. The preparation method comprises the following steps: proportionally adding oxalic acid and V2O5 into 100mL of deionized water, adding NH4H2PO4 into the solution, adding NaF into the solution, carrying out hydrothermal reaction, and carrying out centrifuge washing, drying and the like to obtain the vanadium oxygen sodium fluorophosphate nano material. The synthesis method is simple, and is not related to high-temperature calcination and other high-energy-consumption processes. The synthesized fluorophosphate material has uniform shape, and the shape can be controlled by adjusting the reaction conditions. The nano quadrangular-prism material can be used in sodium ion battery cathode materials. The invention is characterized in that the nano-size material greatly shortens the ion diffusion path, enhances the ion diffusion rate, has larger contact area between the electrode and electrolyte, and thus, has excellent cycle performance and magnification performance.