Abstract: The experimental results on rocks at a temperature equal to the earth's crust indicate that as long as a cyclic load is applied on rocks, there no monodromic correlation would be appeared between stress and strain. Thus the recent tectonic stress and strain fields are changing, now extensively, now weakly. For this reason, there is impossible for the earth stress stations for long-term continuous observation at the fixed points to evaluate the earth stress by the strain, thus a selective method for measuring elasticity and a stress balance method are necessary in determining stress state.