βGa2O3 nanodot array films on intrinsic GaAs substrates have been presented by combining thermal oxidation and MOCVD technology, which does not involve metal catalysts or complex etching. Morphological features of the prepared films were characterized and analyzed by scanning electron microscope (SEM). It is found that the βGa2O3 nanodot array films show a pentagonal columnar structure. Xray diffraction, Raman vibration, and photoluminescence were performed on the prepared samples, and the results show that the crystal quality of the films is optimized with the increase of MOCVD growth temperature and Ⅵ/Ⅲ ratio. The finite element method (FEM) simulations verify that the βGa2O3 nanodot array films are highly light trapping. The nanodot array films prepared by this process show high specific surface area with high light trapping.