Raman spectroscopy was used to measure residual stress of carbon layer on SiC fibre embedded longitudinally in SiC(f)/Ti-22Al-26Nb composites with different reaction layers. By measuring the band shifts of carbon layer, the residual stress arising from thermal expansion mismatch was also determined from the SiC fibre. Results show that as the thickness of reaction layer increases the interfacial residual stress dramatically decreases. Finite element analyses have similar results with the test