In this paper, the repair capacity of SMA wire by using internal and external installation was studied. The SMA wires were embedded in epoxy resin and silicon cement mortar beams made of polymer clay, and then three-point bending test was conducted on the composite beam. The ability of beams which embedded SMA wires was also studied. On the other hand, the SMA wires were installed in the external of the epoxy polymer clay cement mortar, then three point bending test was also used and its self-repair ability was also studied. The results show that the crack can be repaired very well under these two methods. If there are cracks in existing buildings, we can use an external installation method to repair them. In order to ensure the new buildings crack free, both methods are feasible.