This paper described the synthesis of vanadium dioxide (VO2) thin films on mica substrates with different annealing temperatures by an organic sol-gel method. We performed X-ray diffraction, scanning electron microscope and optical transmission measurements to investigate the effect of the annealing temperature on the crystalline structure, morphology, and phase transition properties of these films. The results showed that a polycrystalline structure with high crystallinity and compact surface at the annealing temperature of 500 degrees C. The film exhibited a V6O13 phase and a flat surface with small grain size at 440 degrees C. By contrast, the VnO2n-1 appeared when the annealing temperature at 540 degrees C, and the film surface split into segregation of spherical grain and aggregates of continuously dendritic particles. Accordingly, the optimal annealing temperature was 500 degrees C using the organic sol-gel method. And it turned out that the films mainly contained VO2 (M) phase at room temperature with high content of V4+ valence. Particularly, the films showed different changes in the infrared transmittance and hysteresis width during the phase transition. The largest transformation of the infrared transmittance before and after MIT was 73%, while the narrowest temperature hysteresis width was 8 degrees C at 500 degrees C. (C) 2013 Elsevier B.V. All rights reserved.