VO2(B) nanobelts have been successfully prepared in V2O5 and water mixed suspension assisted by polyvinyl alcohol (PVA) via a mild hydrothermal approach. The as-obtained VO2 nanobelts are several hundred nanometers to several micrometers long, typically 100-300 nm wide and about 20-30 nm thick. It was found that PVA could not only act as the reducing reagent but also as the structure-directing reagent. Besides, the PVA-assisted solid-solution-solid (SSS) transformation mechanism was proposed to illuminate the possible formation mechanism of VO2(B) nanobelts. Furthermore, the electrochemical properties of VO2(B) nanobelts were studied and they exhibited a high initial discharge capacity of 268 mAh/g, indicating that VO2(B) nanoblets are promising electrode materials in lithium battery.