Abstract: The shape memory effect(SME) in Cu-Zn alloy was studied by the twisting deformation method and electric resistance methods. The results show that when the temperature above M_s, there is no thermoelastic mar tensite(TEM), but show perfect SME, so that the SME is entirely caused by stress-induced martensite (SIM). On the other hand, when the temperature below M_s, though there is TEM transformation, the SME is also mainly caused by the SIM.