From another aspect of piezomagnetic effect-magnetization influencing stress, this paper deals with the seismomagnetie questions. Using the theories of magnetic domain and magneto-elastic coupling, obtains the elastic equilibrium equation containing magnetostrictive effect in the dimension of the earth science. From this, analyses the influence of changing magnetic field upon the stress and the mechanical features of the Curie surface. The model estimation is made for the part of magnetic contribution of the thermal stress. This anomalous stress is enough to influence the occurrence of the earthquake. Finally, from the results mentioned above, also discusses the prediction problems of some earthquakes with source model.