We extend the model Hamiltonian of cubic perovskite manganites to a layered manganite system by considering the anisotropy in charge and spin couplings. By minimizing the total free energy of the system, we have obtained the magnetic ground state of the layered manganite crystal as a function of the anisotropic ratio of charge coupling, . It is found that while each bilayer has a ferromagnetic ground state, the interplane magnetic configuration changes from a ferromagnetic order to an antiferromagnetic order with decreasing . This result can account qualitatively for pressure-enhanced interplane magnetoresistance in layered manganite crystals.