Transport of anisotropic biomolecules and/or charged Brownian particles in periodic porous media is of great importance in the fields of biomedicine, water treatment, and environmental engineering etc. In this paper, we present the modeling of transport of biomolecules in periodic polar arrays based on a numerical analysis of effective mobility. Anisotropic biomolecules are transformed to point-sized Brownian particles through introduction of configurational entropy, and the effective charge and effective transport parameters are calculated using macrotransport theory. As an example, the mobility of short dsDNA fragments in a nano-polar array is calculated. It is demonstrated that when the sizes of the gaps between the nano-poles are similar to or smaller than the size of biomolecules, the configurational entropy has a significant effect on the effective velocity. Difference in configurational entropy in the confined space dominates the partitioning of the molecules. In addition, as the effect of entropic barrier decreases with the strength of external electric field, relatively low voltage is preferred in order to achieve better selectivity.