[en] In this paper, the ablation mechanisms of carbon fiber reinforced E-51 epoxy composite irradiated by repetition frequency laser whose wavelength was 1064 nm were studied, and the effects of maximum power density, irradiation time, frequency and pulse width on the thermal ablation rate were discussed. The thermal analysis results indicate that the resin matrix begins to ablate while the temperature of the composite surface reaches the pyrolysis temperature, which is as low as 300 degree C. The ablation of carbon fiber is caused by vaporization when the temperature reaches vaporization point, while the avoidance of carbon oxidation is attributed to the protection of pyrolysis gas. With the maximum power density or frequency increasing, the thermal ablation rate raises at first and then tends to a certain value. However, the thermal ablation rate gradually descends along with the irradiation time until it approaches a definite value. The carbon fiber will be damaged at lower power density while the enhanced pulse width increases the maximum irradiation temperature. (authors)