Vanadium dioxide thin films have been deposited on sapphire substrates with different orientations by pulsed laser ablation. The samples are analyzed by x-ray diffraction and pole figures to determine epitaxial relationship. The crystal quality is evaluated by RBS/Channeling techniques. The results has shown that the growth of VO2 is of strong substrate dependence, the film on (0001) sapphire substrate exhibits better crystal quality than that on (1120) and (0112) sapphire substrates. The epitaxy can be divided into two processes, the first is surface symmetry determined oriented growth, and the second is in-plane oriented growth dominated by the minimization of in-plane lattice mismatch. More over, different substrates result in different defect microstructures, 120o twin is observed in VO2 film on (0001) substrate while 180o on (1120) and no twin on (0112), which also reflects the surface symmetries of the substrates.