Atomic force microscopy (AFM) has some unique advantages to study the martensitic transformation. In this paper. several aspects of this application have been presented. Firstly, the principle of AFM observation on the surface relief effect is described and then quantitative analysis of surface relief occurred in martensitic transformation is performed from AFM images and the results are compared to those theoretically calculated, showing a good agreement between the experimental data and calculated ones in Fe-Mn-Si SMAs. The effect of "training" on shape memory in Fe-Mn-Si based alloys is analyzed and it is found that the formation of uniformly. distributed martensite plates with the single variant nature is the most important factor to have a good shape memory effect in Fe-Mn-Si SMAs. Finally, we observed the difference in surface relief produced by stress-induced martensite and thermally induced martensite for Fe-Mn-Si SMAs (fec/hep) and Fe-Ni-C alloys (fec/bct).