Vanadium dioxide (VO 2 ) polycrystals on glass substrates were synthesized by radio frequency magnetron sputtering method. The VO 2 polycrystals exhibit sharp a -axis diffraction peaks, characteristics of the VO 2 monoclinic phase, which can imply that highly a -axis textured VO 2 was formed. The characteristics of the electronic transition and hysteresis of the phase transition are described in terms of the morphology and grain boundary structures. The sharpness of the transition and the hysteresis upon heating and cooling are found to be strong functions of the crystal structure and microstructure (grain size and shape).