Abstract: In this paper, the constitutive model by Brinson (1993) is modified, and the constitutive model suitable for shape-memory alloy (AMS) springs is built. Based on the constitutive model, the deformation of SMAsprings is analyzed. It can be seen thatthe stiffness ofSMAsprings is variable under different load and temperature conditions, therefore changing the stiffness of the SMA springs can easily control the resonance frequency of a system.