Abstract: It will spend a lot to conduct systematic research on the effect of various anisotropic formations on borehole deviation by using full-size drill bits to break the rock in the lab. Along with the development of computer hardware and numerical simulation software, in particular the development of finite element software, it gets feasible to simulate the borehole deviation in all anisotropic formations. On the basis of the elastic-plastic mechanics and the rock fragment mechanics, the finite element model dynamically simulating the contact of the tooth surface of tri-cone bits and the downhole rock is established, in which the patterns of anisotropic materials are established representing the rock mechanics characteristics. It is proposed that the critical rock plastic strain value be used to judge whether rock materials are cut or flaked off. Well bore and new borehole surface develop after the units flaked off are removed during the process of dynamic simulation. While dynamically simulating and analyzing the drilling based on the newly established model, lateral force of drill bits and borehole wall is produced due to the interference of anisotropic formations and the formation dip. As a result, lateral deviation of drill bits is caused, and finally borehole deviation is caused. Quantitative simulation results are given. Parameters can be adjusted to simulate and analyze the effect of the different drilling parameters, the anisotropic formations, and the formation dip on borehole deviation. It will provide anti-deviation and fast penetration in anisotropic formations and high inclined formations with theoretical references. In addition, it offers theoretical basis for the design and improvement of anti-deviation devices and the wellbore trajectory control. 