A constitutive relationship has been applied to study the behavior of str uctures and composites of the shape-memory alloy(SMA).The predictability of the constitu tive relationship is confirmed by th e uniaxial and multiaxial examples.The paper gives out the finite element algorithmic implementations,which is appl ied to implement as umat of ABAQUS.As two kinds of applications,CT(compact tensile)and TPB(three point bending)specimens and SMA-fiber reinforced metal matrix and met-al-fiber reinforced SMA-matrix com posites are analyzed.The different distributions of martensite fracti on of the CT specimens and TPB-specimens made of SMAs are expla ined by the different stress characteristics ahead the cracks.The relative study on the SMA composites shows that the bulk mechanic behavior depends on the volume of SMA and the non-SMA matrix /fiber pro perties.