Thin-walled elements of shape memory alloys (SMA), which are under compressive stress, are very prone to buckling at thermoelastic martensitic phase transformations. Relevant critical characteristics can be significantly lower values than those critical characteristics of isothermal buckling considered elements of the SPF, even in the least hard – martensitic state material. However, thin-walled elements lose stability and loading other kinds, for example, with respect to the plate – in shear. In this article iisleduetsya case of loss of stability of a rectangular plate of SPF which is in shear conditions caused by direct or reverse phase transformations.