Boron-doped vanadium dioxide (VO2) nanopowders were prepared by the sol-gel hydrothermal method. Effect of process parameters including the hydrogen peroxide (H2O2) concentration, hydrothermal time, annealing temperature, type of boron dopant and boron doping amount on the synthesis of boron-doped VO2 powders was investigated. The structure, morphology and phase transition properties of the boron-doped VO2 powders were characterized by the X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma (ICP), field emission scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The results show that the superior synthesis process parameters are 15% for the H2O2 concentration, 72 h for the hydrothermal time, 600 °C for the annealing temperature, boric acid as the boron dopant, and less than 10 at.% for the boron doping amount. The obtained boron-doped VO2 powders have the size of around 100 nm with the morphology of coral-like structure. The boron atoms successfully replace the vanadium atoms in the VO2(M) lattice. The phase transition temperature is reduced by 7.2 °C, when the actual doping amount is 0.6 at.%.