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 by high-energy ion implantation in LiTaO3 films hinder the enhancement of device performance. In this study, we employed a thermal annealing process to repair the damage in LiTaO3 films and characterize the defects using Raman spectroscopy. Additionally, we analyzed the impact of annealing temperature on the composition and defects of LiTaO3 films. The results demonstrate that thermal annealing effectively repairs lithium vacancy defects and reduces oxygen vacancies in LiTaO3 films.