Abstract: To investigate the effects of the high-speed airflow on the laser ablation characteristics of C/SiC composites, comparative study of laser ablation experiments under different environment conditions, including static air, Mach 1.8, Mach 3.0, Mach 6.0, were conducted by utilizing the joint experiment system integrating the laser and wind tunnel device. Experimental results show that, compared with the static air condition, the high-speed airflow had a remarkable impact on the laser ablation characteristics of C/SiC composites. The “washing effects” induced by the high-speed airflow made the ablation pit wider, deeper, smoother. Meanwhile, the linear ablation rate and mass ablation rate enlarged with the increasing airflow velocity, which was mainly due to the increased sublimation rate and erosion rate caused by the decreased local static pressure and increased dynamic pressure, respectively. Besides, the contrast experimental study of 2D and 3DN C/SiC composites were conducted to investigate the influences of braided structure of C/SiC composites. Results show thatdue to the factors suchas lower heat conduction capacity along the thickness direction, the lower porosity, the ablation resistance performance of 2D C/SiC composites was superior to that of 3D C/SiC.