Active functional group-coated VO2(B) nanorods were successfully synthesized using ammonium metavanadate and oxalic acid solution as the starting materials, by a facile one-pot hydrothermal route for the first time. The results showed the sample consisted of crystalline VO2(E) and amorphous component. The amorphous component contained numerous active functional groups such as O-H, N-H, C=O, and C-O. Furthermore, short V2O3 nanorods were converted by thermal treatment with the active functional group-coated VO2(B) nanorods.