Abstract: Characteristics of laser-induced damage of some optical thin films deposited by e-beam evaporation were investigated in vacuum and atmosphere environments，and the differences of laser-induced damage in two conditions were analyzed and discussed. The results show that compared to normal atmospheric conditions, optical thin films have a decreasing laser induced damage thresholds under vacuum environments. The morphologies of the damages under two conditions are quite different. Gas heat conduction has little influence on the difference of damage thresholds under two conditions. The hydrolysis-induced tension increase and the laser-irradiated nonstoichiometric defects of films in vacuum environments probably result in different laser-induced damages in vacuum and atmosphere environments．