Fundamentals of the unified technology combining plastic forming and heat treatment of materials mainly consist of the metallurgical and mechanical interactions between stress, transformation and deformation, modeling as well as simulations of microstructural and property evolutions. In the present work, taking steel for example, the literatures on ferrite, pearlite, bainite and martensitic transformations under stresses are introduced. Kinetics models and computer simulation of microstructural evolution of ferrite and pearlite transformations under stresses in a 0.38C-Cr-Mo steel are suggested. A discussion is given on deficiency and the modification of Scheil's additivity hypothesis. Phase field theory and its application, as well as the perspective in further study of the unified technology are briefly presented.