The longitudinal thermal expansion characteristics of SiCf/Cu matrix composites without or with Ti6Al4V interlayers were studied, and the microstructures of the specimens after thermal cycles were observed by the scanning electronic microscopy. The results reveal that the interfacial bonding strength between the fiber and the matrix has significant influence on the longitudinal thermal expansion behavior of fiber-enhanced metal-matrix composites. The composites without Ti6Al4V interlayers have unstable thermal expansion behavior and exhibit positive thermal hysteresis behavior after the two continuous thermal cycles due to the interfacial debonding, sliding and expansion of the matrix. While the composites with Ti6Al4V interlayers keep dimensional stable after the two thermal cycles, and their longitudinal coefficients of thermal expansion (CTE) are greatly reduced as well as the fiber/matrix interface keeps stable.