The continuumthermodynamical studies on thethermal-elastic martensitic transformation in shape memory alloys and itsrecent progresses are reviewed in this paper. Within the frame of nonlinearelasticity, the variational method has been applied successfully in studyingthe thermal-elastic martensitic transformations. Some fundamentals of thetheory and main approaches are discussed. The existing problems and possiblefuture directions are analysed. With the deformationgradients of the 24 martensitic variants, the nonlinear elastic theory canbe extended by introducing the multi-well potential energy function todescribe the transition. The related theory and some recent studies on theeffect of the interfacial energy and the non-local energy on themicrostructures and the phase transition process are discussed.