The interfacial reaction of Ti-6Al-4V composites reinforced with Chinese SiC fiber was investigated by means of scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The reaction product of TiC with fine grains and large grains was identified between the Ti-6Al-4V matrix and the C-coating of the SiC fiber. However, in the interfacial reaction zone of the SiCf /Ti-6Al-4V composite in which the SiC fiber has no C-coating, from SiC fiber to Ti-6Al-4V matrix, there exist fine grains of TiC+Ti5Si3, large grains of TiC and Ti3SiC2. The thickness of the interfacial reaction zone was measured and the interfacial reaction mechanism was discussed.