The C/C composite was prepared by chemical vaper infiltration (CVI) followed by pitch impregnation and high pressure carbonization (HPIC) using needled non-woven carbon fiber felt preform. The microstructure of composites was characterized by micro-computed tomography (μ-CT) and scanning electron microscope (SEM). The ablation resistance at different cross sections was evaluated using plasma ablation test. Typical cross sections of the experiment were X-Y section (0°, perpendicular to needing direction), Z section (90°, parallel to needing direction) and cross sections (23°, 45°, 68°) of composites, respectively. The results presented that the porosity of the C/C composites was as low as 4%, and 98% of the internal pores was smaller than 20 μm. The ablation resistance at different cross sections improved first and then decreased from X-Y section (0°) to Z section (90°). The cross section at 68° showed the best ablation resistance, at which the mass and linear ablation rates were 0.050 g/s and 0.056 mm/s, respectively. The best ablation resistance is attributed to the icicle-like ablation mode of carbon fiber, which indicates that fiber arrangement at the cross section has significant impact on ablation resistance of C/C composites.