Abstract: Cu(1.42%Ti) films were deposited by magnetron sputtering on Si(100) and SiO2 substrates. The microstructure and interfacial reaction were investigated before and after annealed at 573～773K. X-ray diffraction revealed Cu(111) and Cu(200) peaks for as-deposited Cu(Ti) films and Ti promoted the (111) texture of Cu films. For the annealed Cu(Ti)/Si system,the thermal stability of films decreased because of Cu3Si formed at 573K,which was due to the purifying effect of small amount of Ti at the interface between the film and substrate. While for the Cu(Ti)/SiO2 system annealed till 773K,the film exhibited good thermal stability. These results were also proved by observations of cross-sectional morphologies and the Auger survey spectrum of the interface.