Lithium tantalate(LiTaO3) single-crystal thin films are utilized for high-Q and low thermal drift narrow-band RF filters based on crystal ion slicing(CIS) technology. However, defects and lattice damage caused byhigh-energy ion implantation in LiTaO3 films hinder the enhancement of device performance. In this study, we employeda thermal annealing process to repair the damage in LiTaO3 films and characterize the defects using Ramanspectroscopy. Additionally, we analyzed the impact of annealing temperature on the composition and defects ofLiTaO3 films. The results demonstrate that thermal annealing effectively repairs lithium vacancy defects and reducesoxygen vacancies in LiTaO3 films.