Based on the scales theory of electromagnetic field, we first introduce a new coordinates system, named scales coordinates system according to the elements of the dielectric tensor of the anisotropic medium. In the scales coordinates system, the anisotropic medium is changed to isotropic material, using the expression of the potential of an electric charge in presence of the isotropic medium and the scales invariants, the electric potential of a charge in the anisotropic medium is obtained. Then the electric potential of an electric dipole with a general direction are obtained by using the obtained potential formula in the anisotropic material to two electric charges with the opposite symbol and the method of Taylor's series expansion. By let the elements of dielectric tensor equal to each other, the anisotropic material will be an isotropic material, the obtained result completely equal to the those of a charge in free space in the available literatures, and the correctness of this obtained results are demonstrated. Finally some numerical results of the obtained electric potential of the electric dipole change with the anisotropic tensor are presented. The method used in this article will provide a new way of studying the electrostatic filed in the presence of anisotropic medium.