The proposed model is based on the structure-analytical theory of strength (Likhachev and Malinin, 1993). This theory postulates the deformation law on the micro-level, and the macro-strain is calculated by neutralization of all micro-strains related to the volumes with different crystallographic orientations and parameters of the transformation. A grain is considered as a major structural element of a polycrystal. Phase deformation due to the martensitic transformation, accommodation of martensite and macro plastic deformations produced by dislocation slip are calculated. This approach allowed to describe main mechanical properties of shape memory alloys, among them the transformation plasticity, shape memory, pseudoelasticity and two-way-memory effect. As the evolution equations for the kinetics of transformation are formulated with an account for the basic laws of thermodynamics and symmetry of austenite and martensite, good results were obtained both for the thermoelastic TiNi-type alloys and FeMn-type alloys undergoing the burst-type fcc-hcp transformation. The results of modelling have shown that symmetrical considerations can explain the transformation plasticity (strain accumulation due to a transformation in a stressed specimen) while direct or reverse transformations, the incompleteness of the strain recovery in the subsequent reverse or direct transformation in FeMn-type alloys.