Abstract: The annealing process of the Al-carbon steel-Al sandwich strip produced by roll cladding was investigated. The effects of annealing temperature/time on the growth behavior of interfacial intermetallics were analyzed by metalloscope, SEM and XRD with the main mechanical properties tested. The results showed that the critical forming temperature of the intermetallics is 420°C, at which the main compound is of FeAl3 phase and the layer thickness is about 10μm. The optimum annealing schedule obtained from testings is 420°C for 20 min. The elongation of the strip after annealing comes up to 18.28% and, however, it will be lower than 5% if the brittle intermetallics distribute continuously on interfaces.