Abstract: In this paper, a kinetics model for martensitic transformation in shape memory alloys(SMAs) is established on the fact that the partial derivative of martensite fraction with respect to temperature is in linear relationship with the partial derivative of free energy difference with respect to temperature. The model is compared with Tanaka's model and Liang's model. All the models are implanted in the SMAs reinforced composite model and the result shows that the model established in this paper agrees well with experimental observations.