Abstract: In this paper,a global stress field caused by the change of rate of the earth's rotation is calculated using finite element method.The principal stress resulting from the change of centrifugal inertial force is South-North and East-West oriented,and the magnitude of the stress may reach to tens to several hundreds MPa.The principal stress caused by latitudinal inertial force for a homogeneous earth is Northeast and Northwest oriented.With a varying crustal thickness along the longitude,there will be a zoning of the stress field caused by latitudinal inertial force with the resulting 4 tension zones corresponding to the locations of the present 4 Mid oceanic ridges.