Abstract: The dense C/Al composites have been fabricated by hot isostatic pressing (HIP) with which the C/Al precursor wires were encapsu-fated in a glass tube.It was observed that the fracture of the C/Al composite possesses a low strength and smoothness.The reaction layer of the interface was studied with scanning electron micro scope (SEM).The transmission electron microscope (TEM) and X-ray energy spectroscope (XES) were used to observe and determine the morphology and the composition of the interface.It was found that the interface was divided into two layers.TiB₂ interface was diffused to the both sides of the interface and the compositions of the carbon fiber and matrix also were diffused through the interface. Beside sthe electron diffraction (ED) was used to study the inter-face structure.The structure compositions were defined as TiO₂, TiC,TiB₂,r-Al₂O₃, Ti, B and C.The chemical compositions were analyzed by auger electron spectroscopy (AES) and secondion masses spectroscopy (SIMS).The composition determined were used by SIMS and ED with a nearly result except founding Al₄C₃ at SIMS.