Abstract: The shear strength developed in a landslide is usually anisotropic and nonlinear. The anisotropy is primarily dueto the process of sedimentation predominantly followed by one-dimensionalconsolidations. The nonlinearity could be attributed to ``interlocking'' or``dilatancy'' of the material, which is generally dependent upon the stresslevel. In the paper, a new anisotropci function was been developed. An analytical method considering both anisotropy and nonlinearity ofthe failure envelopes is presented in the paper. The nonlinear failureenvelopes can be obtained from routine triaxial tests. In a SPREADSHEETsetup, the authors developed an approach that uses the Janbu's GeneralizedProcedure of Slice and incorporates anisotropic and nonlinear failureenvelopes. In the analysis, an equivalent Mohr-Coulomb linear relation isobtained by drawing a tangent to the anisotropic and nonlinear envelope. Anillustrative example is given to show the feasibility and numericalefficiency of the method.