Shape memory alloy (SMA) is a new intelligent material and is used widely in various structures. But the constitutive model of SMA is so complex and particular that it is difficult to calculate by finite element software. In this paper, a special constitutive model of SMA is chose and the constitutive variables are discretized. Through the derivation, it is made possible that the constitutive relation of SMA is put into the UMAT (user-defined material mechanical behavior) subroutine in ABAQUS. So it is available to calculate the structure contained SMA by finite element method.