Abstract: Acoustic emission caused by the motion of magnetic domain walls in a ferromagnetic material ralates to magnetostriction effect This is called MAE (Magnetomechanical Acoustic Emission) Magnetomechnical acoustic emission depends on the microstruction, chemical composition and stress state of material.It can be used for non-destructive testing. As a newly developing non-destructive testing technique for residual stress measurements, it has a advance over other methods such as x-ray diffraction and acoustic surface wave. This paper mainly describes the chractries of MAE of steel with different carbon content and Fe-Ni alloys with different nickel content, influence of chemical composition,stress state、plastic deformation and heat treatment on MAE.A model of MAE origin mechanism is given in this paper according to the experimental results anb is discussed in detail.