Abstract: Semi-analytic soutions forultimate bearing capacity of complicated foundaations are pre-sented.A limit equilibrium principle for complicated foundations is eestablished with a strength criterion of nonhomogeneous, nonlinear,anisotropic rocks and soils. Formulas for slope of slip lines and differen-tial equations of stresses along slip lines are obtained. By integrating these equations and analysing variation of stress in slip region,the ultimate bearing capacity formulas of anisotropic foundations with and without internal friction and nonlinear foundations are derived ,and bearing capacity coefficients of various kinds of complicated foybdations are obtained.It is indicated that hte bearing capacity of found-ations is decreased by anisotropy and that of nonlinear foundations may be determined by the ratio ofcompressive to tensile strength. Results of this paper, when simplified for linear isotropic foundations,are in good agreement with some classical solutions.