Abstract: Considering the three-dimensional inhomogeneity of the earth's crust, three dimensional finite element method is applied to an analysis of the earth's crustal stress field, gravity (including gravitation and centrifugal force) and temperature effect being taken for the external load. Results:(1) The crust is absolutely dominated by compressive stress;(2) The latitudinal horizontal stress increases with increase in depth, and is independent of latitude;(3) The longitudinal horizontal stress oncreases with increase in depth, and decreases with increase in latitude at the same depth;(4) The degree of anisotropy of horizontal stress decreases with increase of latitude;(5) In the surficial and upper layers of the crust, high horizontal stress is widespread.