Abstract: The magnetostriction methode which is bases on. the magnetostriction effect and anisotropic magnetical beviour of the ferromagnetic determination is presentted. The magnetic signal response during fatigue is examined by the special-made probe and the data process system. It has been found that a sudden signal change occurs at certain fatigue level which is correspoending to the certain level of plastic deformation. It is sure that after systematic standardization the magnetostriction method can be applied to the fatigue life estimate of the engineering materials and the structure members.