Laser-materials interactions are influenced by environmental factors.In order to research the laser ablation mode and mechanism of carbon/epoxy composite in vacuum and atmosphere environment,laser irradiation experiments are preformed in two environments.Under different irradiation energy levels,ablation characters of composites in different environments are investigated and the transient temperature data are obtained.Microphotography is used to study the material change.The experimental results show that laser ablation mode of composite materials are closely related to energy levels of incident laser beam.Under low irradiation energy level,though the surface ablation morphologies are different with each other,the transient thermal responses of composites are almost the same.Under high irradiation energy level,ablation morphologies are different obviously with each other.In vacuum environment,epoxy is heated to a high temperature,and then thermal decomposition and volatilization are observed.The phenomenon of composites delamination is obvious in vacuum environment.In atmosphere environment,epoxy is reacted with oxygen,and the phenomenon of composites delamination is not obvious.Finally the difference between the laser ablation modes of the composites in different environments is analyzed according to microcosmic morphologies.The experiment results will be useful to develop theoretical model.