α- Ga₂O₃ heteroepitaxial thin films on sapphire substrates with different crystal planes were prepared by mist-chemical vapor deposition (Mist-CVD) technique. The phase, optical properties and surface morphology of the samples were investigated by XRD, SEM and UV-Vis. The temperature windows for growing pure phase α-Ga₂O₃ thin films on C, M, A and R-plane sapphire substrates within 600 ℃ are 420~480, 480~550, 590~600 and 540~600 ℃, and optical band gaps of the pure phase α-Ga₂O₃ thin film are 5.12, 5.23, 5.25 and 5.21 eV, respectively. Compared to C-plane sapphire substrates, epitaxial α-Ga₂O₃ thin films on M, A and R-plane sapphire substrates require higher growth temperatures, and the bandgap width of the films obtained on M, A and R-plane sapphire substrates are larger. The SEM results of the sample surface show significant differences in the surface morphology of α-Ga₂O₃ thin films with different crystal planes, and there is a "continuous layer+large island" structure on the α-Ga₂O₃ thin film grown on C-plane sapphire substrate. The study of epitaxial α-Ga₂O₃ thin films on sapphire substrates with different crystal planes in this article provide valuable reference for the application of α-Ga₂O₃ materials.