The ground state energy of weak-coupling polaron in a parabolic quantum dot considering the phonon dispersion is calculated using the squeezed-state variational approach. The variational approach we applied is based on two successive canonical transformations and using a single-mode squeezed-state type unitary transformation to deal with the bilinear terms which we neglected usually. The relations of the ground-state energy of polaron in a parabolic quantum dot on the electron-LO-phonon coupling constant

the coefficient of phonon dispersion and the confinement length are derived in the electron-LO-phonon weak-coupling case.