Interfacial behaviors of SiC fiber reinforced titanium matrix composites during thermal exposure were investigated by SEM, EDS and XRD. The effect of C coating was mainly analyzed. The results showed that C coating can be an effective barrier of the diffusion of Si element. And the C coating of SCS-6 SiC reinforced Ti6Al4V will be almost completely consumed after thermal exposure for 25 hours at 925°C. TiC will be found in the interface when the C coating exists. After C coating is completely consumed, there is Ti3SiC2 occurring besides TiC and the interfacial debonding strength is high. However, without the protection of C coating, the fibers will be consumed and their longitudinal tensile strength will be decreased, and this will affect the service performance of the composites.