A novel finite volume method is presented to investigate the effect of anisotropic conductivity on the potential distribution of the scalp. The second-order interpolation of the tetrahedral mesh is used to avoid employing the secondary element. The calculation precision is enhanced by using the Gaussian integration. To avoid the geometric singularity, the triangular prism is employed in place of the conventional hexahedron mesh. With the method, the spherical models as well as the realistic head models are simulated. The calculation results indicate that the anisotropic ratio and the position of dipole sources have great influence on the potential distribution in the electroencephalogram.