In this study, Ta2O5 sol was synthesized from TaCl5 precursor, and its time dependence of the viscosity, particle size distribution and photoluminescence spectra were studied. Then, Ta2O5 films were prepared using this sol and were succeeding annealed at different temperatures without carbonization and cracks. It was found that the films had good properties such as high transparency, small absorption and high laser-induced damage threshold (LIDT). The LIDT decreased with the increase of the annealing temperature probably due to the acetylacetone in the films. The laser-induced damage morphologies of the films after annealing were different. With the annealing temperature increase, the dominant factor of the laser induced damage transformed gradually from the stress to the thermal. According to the LIDT and damage morphologies, a structure evolution model of the films annealed at different temperatures was proposed. (C) 2015 Elsevier B.V. All rights reserved.