Abstract: An increment shape memory alloy (SMA) constitutive relation is developed based on the SMA constitutive model produced by the authors; a new micromechanical constitutive model of composite reinforced by long SMA is constructed by using the relations of micromechanics; mechanical properties of the composite are investigated by using the new model, and some quantitative conclusions, especially the variation of stress in the constitution, are given, which is helpful to design the intelligent composites.