The current work designs a Gassian trial wavefuntion for Bose-einstein condensates (BEC) with dipole-dipole interaction. The wavefunction is reasonably regarded as that of the dipole crystal under high particle density condition. Hartree-Fock mean field approximation has been modified under the consideration of the overlaping effect of non-orthogonal wavefunction. The minimum energy of crystalline phase can therefore be found by numerical computations and phonon spectrum evaluation. These shear and compression modulus are shown to be definitely positive. Thus, it is concluded that quasi-2D dipolar crystal is a stable state under high condensed density.