Abstract: Based on the scales theory of electromagnetic waves, an anisotropic dielectric ellipsoid is reconstructed into an isotropic one in both electromagnetic and shape parameters. An analytical expression of the electric field inside the anisotropic dielectric ellipsoid is then presented by using the scales relation between electromagnetic fields of the two ellipsoids, and it agrees well with previously published results. The angle between directions of electric fields inside and outside the anisotropic ellipsoid is also derived. Simulations show that the direction of the external electric field has little effect on the internal field, while the dielectric tensor influences both the direction and amplitude of the internal field remarkably.