Naturally formation of soil deposits leads to anisotropy and heterogeneity in their properties. The aim of this study is modeling of soil having anisotropic and heterogeneous strength using finite difference method to estimate the effect of these on slope stability in undrained condition. In this study the soil cohesion is considered as an anisotropic and heterogeneous variable and assumed to have a deterministic trend with depth and different values in any directions per depth. However, the anisotropy of cohesion is considered by generalizing the isotropic Mohr- Coulomb model to anisotropic one. The study performs on a slope in undraned condition and results indicate that the importance of anisotropy and heterogeneity of soil strength parameters on slope stability. Taking account of anisotropy and heterogeneity leads to proper and economic analysis and design of slope stability so that the safety of factor in the case of anisotropy equal to 2(AF=2) was approximately 40% greater than in the case of fully isotropic.