Abstract: In this paper we have discussed the deformation of reference system,i.e.,thegeoid,due to earthquake dislocation and have given some numerical results on changesof the geoidal height and the deflection of vertical and variations of the geoidal height with dip angles of the dislocation plane.In the presence of the geoida deformation we have further presented a method treating inversion of source parameter of earthquake dislocation with data of apparent displacement and gravity change on the ground and applied it for determining sourse parameters and changes of geoidal height for the Tangshan earthquake.The results indicate that based on geodetic data inversion of source parameters of earthquake dislocation model is not only theoretically serious,but also practically significant.