The present paper is concerned with the evaluation of ablative performance of 3D carbon/carbon composites.The morphology and microstructure of ablative samples are investigated by on-line real-time monitoring system and SEM techniques.The results show that the ablation of 3D C/C composites is as a result of integration of thermo-chemical ablation and mechanical denudation.Mechanical denudation is dominant at the edge of sample surface,and while thermo-chemical ablation and mechanical denudation are coupled in the center region of sample surface.It has obvious discrepancy for ablative performance between carbon matrix and carbon fiber.The ablation resistance of carbon fiber is much better than the carbon matrix’s.The ablative performance of 3D C/C composites displays clear anisotropy.It is better in the longitudinal direction of 3D C/Cs because the fiber bundle can resist the ablation until it loses the support of the surrounding matrix.On the contrary,the ablation resistance is poor in the radial direction of 3D C/Cs because the surface delamination is dominant in the course of ablation.