Ultrathin 2D nanostructures have shown many unique properties and are attractive for various potential applications. Here, we demonstrated a strategy to synthesize ultrathin VOx nanosheets. The as-obtained ultrathin VOx nanosheets showed a large Brunauer-Emmett-Teller (BET) surface area of 136.3 m2 g(-1), which is much larger than that of 1D multilayer VOx nanotubes. As a proof of concept, these hydrophilic ultrathin nanosheets were applied in water treatment and exhibited excellent absorption capability to remove Rhodamine B (RhB) in wastewater owing to their large specific surface area, good hydrophilic property, and more negative zeta potential. In addition, this method could be generalized to prepare other 2D nanostructures with great potential for various attractive applications.