The work aims to study the effects of annealing treatment on the structure and tribological properties of dia-mond-like carbon thin films and discuss the inter relation. Diamond like carbon (DLC) films were deposited by plate hollow cathode plasma enhanced chemical vapor deposition method with C2H2 and Ar as the reaction gas source. Then, the DLC thin films were annealed in the atmospheric environment with different temperature. The structure, stress and tribological properties of the DLC thin films before and after annealing were investigated and tested by scanning electron spectroscopy (SEM), Raman spectroscopy, metalloscopy, stress analyzer and ball-on-disk tribotester. After annealing at lower temperature (q≤300 ℃), the content of sp3-C in the thin films slowly decreased as the annealing temperature increased and the structure of DLC films had no significant changes. However, the internal stress decreased and the friction coefficient firstly decreased and came to the stable state earlier. At 400 ℃ annealing temperature, the structure of DLC thin films changed obviously and oxidation was observed on the surface. The initial friction coefficient was high and the friction coefficient of thin films decreased as the friction time extended. Meanwhile, the stable friction coefficient (~0.16) was high for the DCL thin film annealed at lower temperature. At 450 ℃ annealing temperature, the structure of thin films changed significantly and serious oxidation was observed. The tribological properties was seriously deteriorated and came to failure quickly. The annealing temperature significantly affects the structure and tribological properties of DLC thin films.