Abstract: The flexural behavior of 2D carbon-carbon (C/C) composites fabricated by CVI was investigated using a three-point bend test, and the fracture surface and interface of the composites were observed by SEM. By analyzing the effects of the fiber-matrix interface and the sample density on the mechanical behavior, it is revealed that the fracture modes of 2D C/C composites change from shearing and delamination failure to tensile breakage with increasing densification degree. The results also show that the density has a great impact on the strength and modulus rather than the flexural deflection. In fact, the flexural deflection of 2D C/C composites depends on the performance of the pyrocarbon and the interfacial bonding between fibers and matrix.