The invention discloses a method for preparing vanadium pentoxide-based nanosheets, and belongs to the field of functional nanomaterials. The method comprises the following preparation steps: firstly,dissolving vanadium triacetylacetonate and tin tetrachloride pentahydrate in N,N-dimethylformamide, and performing magnetic stirring for 1 to 2 hours until a uniform and transparent solution is formed; secondly, transferring the solution into a stainless steel autoclave lined with polytetrafluoroethylene, reacting in a baking oven, washing the solution with anhydrous ethanol after the reaction, and drying; finally, putting ground powder into a muffle furnace for calcining treatment to obtain V2O5-SnO2 nanosheets with high crystallinity. The method has the advantages of short production cycle,low cost, easiness in operation and mild reaction conditions; the material has higher performance, and has a broader application prospect in the fields such as energy storage and catalysis.